Semiconductor light emitting device, method for manufacturing same, and method for forming underlying layer

ABSTRACT

A method of making a semiconductor light emitting device including: (A) an underlying layer configured to be formed on a major surface of a substrate having a {100} plane as the major surface; (B) a light emitting part; and (C) a current block layer, wherein the underlying layer is composed of a III-V compound semiconductor and is formed on the major surface of the substrate by epitaxial growth, the underlying layer extends in parallel to a &lt;110&gt; direction of the substrate, a sectional shape of the underlying layer obtained when the underlying layer is cut along a virtual plane perpendicular to the &lt;110&gt; direction of the substrate is a trapezoid, and oblique surfaces of the underlying layer corresponding to two oblique sides of the trapezoid are {111}B planes, and the top surface of the underlying layer corresponding to an upper side of the trapezoid is a {100} plane.

RELATED APPLICATION DATA

This application is a division of U.S. patent application Ser. No.12/208,776, filed Sep. 11, 2008, the entirety of which is incorporatedherein by reference to the extent permitted by law. The presentapplication claims priority to Japanese Patent Application JP2007-239801 filed in the Japan Patent Office on Sep. 14, 2007, theentirety of which also is incorporated by reference herein to the extentpermitted by law.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor light emitting device,a method for manufacturing the same, and a method for forming anunderlying layer.

2. Description of the Related Art

As a semiconductor laser having low threshold current I_(th), asemiconductor laser having a separated double hetero junction (SDH)structure that can be formed through one time of an epitaxial growthstep (hereinafter, referred to as an SDH semiconductor laser) is knownfrom e.g. Japanese Patent No. 2990837.

For this SDH semiconductor laser, initially a projection part extendingalong the {110}A plane direction is formed on a substrate having the{100} plane as its major surface. Subsequently, through crystal growthover the major surface of this substrate, a light emitting part arisingfrom stacking of compound semiconductor layers is formed on the {100}plane of the projection part (for convenience, referred to as theprojection surface). The light emitting part has e.g. a structurearising from sequential stacking of a first compound semiconductor layerof a first conductivity type, an active layer, and a second compoundsemiconductor layer of a second conductivity type. The sectional shapeobtained when this light emitting part is cut along a virtual planeperpendicular to the extension direction of the projection part is e.g.a triangle, and the side surface (oblique surface) of the light emittingpart is the {111}B plane. In general, the {111}B plane is known as anon-growth surface in MOCVD (Metal Organic Chemical Vapor Depositionreferred to also as MOVPE (Metal Organic Vapor Phase Epitaxy)), exceptfor special crystal growth conditions. Therefore, in the case of the SDHsemiconductor laser, after the light emitting part whose side surface isthe {111}B plane is formed, “self growth stop” of the crystal growth ofthe light emitting part is kept even if the MOCVD is continuedthereafter. The inclination angle (α) of the {111}B plane is 54.7degrees.

In the present specification, the crystal planes shown below arerepresented as the (hkl) plane and the (hk-l) plane, respectively, forconvenience.

(hkl)plane

(hk l)plane

In addition, the directions shown below are represented as the [hkl]direction and the [hk-l] direction, respectively, for convenience.

[hkl]direction

[hk l]direction

On the other hand, the {100} plane part as the major surface of thesubstrate except the projection part (for convenience, referred to asthe recess surface) does not involve a non-growth surface. Thus, if theMOCVD is continued, a compound semiconductor layer formed throughcrystal growth from the recess surface will completely cover the lightemitting part in the self growth stop state in time. The compoundsemiconductor layer formed through crystal growth from the recesssurface has, on the second compound semiconductor layer, a structurearising from sequential formation of a layer for adjustment of thecurrent block layer position (hereinafter, referred to simply as theadjustment layer), a current block layer, and a burying layer. Ingeneral, controlling the thickness of the adjustment layer makes itpossible to form a structure that permits current injection only to theactive layer of the light emitting part through formation of the currentblock layer at an intermediate phase before the compound semiconductorlayer formed through crystal growth from the recess surface covers thelight emitting part (in particular, when the upper surface of thecompound semiconductor layer is about to reach both the side surfaces ofthe active layer formed in the light emitting part).

In this manner, for the SDH semiconductor laser, the respective compoundsemiconductor layers can be formed based on one time of a crystal growthstep. In addition, the active layer can be completely surrounded bycompound semiconductor layers favorable for light confinement byselecting materials whose energy band gaps are sufficiently wider thanthat of the active layer, i.e., materials having lower refractiveindexes, as the materials used for the compound semiconductor layersthat vertically sandwich the active layer in the light emitting part(the first compound semiconductor layer and the second compoundsemiconductor layer) and the materials used for the current block layer,the burying layer, and the adjustment layer located outside the lightemitting part. Due to this feature, the shape of a beam emitted from thesemiconductor laser whose light emitting surface is the end surface ofthe projection part can be brought close to a perfect circle. That is,as the far field pattern (FFP), the following relationship can beachieved.

θ//≈θ⊥

Furthermore, depending on e.g. the efficiency of coupling with a lens,it is often needed that the shape of a beam emitted from thesemiconductor laser is an ellipse. For such a case, the θ// of the FFPcan be set small e.g. by employing a so-called flare-stripe structure,in which the width of the projection part near the ends of theprojection part is increased (refer to e.g. Japanese Patent No.3399018). Moreover, employing the flare-stripe structure can achievehigh light output.

SUMMARY OF THE INVENTION

As described above, for the SDH semiconductor laser, initially aprojection part extending along the {110}A plane direction is formed ona substrate having the {100} plane as its major surface (see FIG. 58A).Therefore, the size of the light emitting part is defined by the width(W_(P)) of the projection part. On the other hand, the width (W_(A)) ofthe active layer is determined based on the specification of the SDHsemiconductor laser. Therefore, if the width (W_(P)) of the projectionpart is small and the active layer having a desired width (W_(A)) isformed, the distance (H₁) from the active layer to the projection partis short naturally (see FIG. 58B). The parameters H₁, W_(P), and W_(A)have the following relationship.

H ₁={(W _(P) −W _(A))/2}×tan(α)

If the distance (H₁) from the active layer to the projection part isshort, the following problem arises. Specifically, light generated bythe active layer is absorbed by the substrate as the projection part,which leads to an incomplete light confinement effect and thus thelowering of the light emission efficiency (the slope efficiency,represented by “light output/injected current”).

The height (H₂) of the light emitting part is also defined by the width(W_(P)) of the projection part. The parameters H₂ and W_(P) have thefollowing relationship.

H ₂=(W _(P)/2)×tan(α)

Therefore, if an SDH semiconductor laser is manufactured based on aprojection part having a low height (H₀) and a large width (W_(P)),i.e., having a so-called low aspect ratio, as shown in FIG. 59A, therewill be no room for formation of a current block layer on the sidesurfaces of the active layer as shown in FIG. 59B.

There is a need for the present invention to provide a semiconductorlight emitting device, a method for manufacturing the same, and a methodfor forming an underlying layer that all allow enhancement in the designflexibility of the underlying layer (base part) for forming the lightemitting part and allow achievement of high light emission efficiency.

According to a first mode of the present invention, there is provided asemiconductor light emitting device that includes:

(A) an underlying layer configured to be formed on the major surface ofa substrate having the {100} plane as the major surface;

(B) a light emitting part configured to arise from sequential stackingof a first compound semiconductor layer of a first conductivity type, anactive layer, and a second compound semiconductor layer of a secondconductivity type above the top surface of the underlying layer; and

(C) a current block layer configured to be formed above a part of themajor surface of the substrate on which the underlying layer is notformed and cover at least the exposed side surface of the active layerof the light emitting part, wherein

the underlying layer is composed of a III-V compound semiconductor andis formed on the major surface of the substrate by epitaxial growth,

the underlying layer extends in parallel to the <110> direction of thesubstrate,

the sectional shape of the underlying layer obtained when the underlyinglayer is cut along a virtual plane perpendicular to the <110> directionof the substrate is a trapezoid, and

the oblique surfaces of the underlying layer corresponding to twooblique sides of the trapezoid are the {111}B planes, and the topsurface of the underlying layer corresponding to the upper side of thetrapezoid is the {100} plane.

In the semiconductor light emitting device according to the first modeof the present invention, it is desirable that the energy band gap(E_(g)) of the material of the underlying layer be larger than theenergy band gap (E_(g-0)) of the material of the substrate. Thiscondition will be referred to as “energy band gap condition-A,” forconvenience.

Furthermore, in the semiconductor light emitting device according to thefirst mode of the present invention including the above-describedpreferred mode, it is desirable that the energy band gap (E_(g)) of thematerial of the underlying layer be larger than the energy band gap(E_(g-1)) of the material of the first compound semiconductor layer.This condition will be referred to as “energy band gap condition-B,” forconvenience.

In the semiconductor light emitting device according to the first modeof the present invention including the above-described various preferredmodes, it is preferable that the III-V compound semiconductor of theunderlying layer contain, as an element, at least one of arsenic (As),antimony (Sb), and bismuth (Bi), and aluminum (Al). Alternatively, it ispreferable that the III-V compound semiconductor of the underlying layercontain at least phosphorus (P) as an element. As the combinations of(the III-V compound semiconductor of the substrate, the III-V compoundsemiconductor of the underlying layer, the III-V compound semiconductorof the first compound semiconductor layer) in the former configuration,the following compositions can be cited, as long as energy band gapcondition-A or energy band gap condition-B is satisfied.

Composition-A: (GaAs, Al_(x1)Ga_((1-x1))As, Al_(y)Ga_((1-y))As)

[0<x1≦1, 0<y≦1, and (E_(g) of GaAs)<(E_(g-0) of Al_(x1)Ga_((1-x1))As),(E_(g) of Al_(x1)Ga_((1-x))As) (E_(g-1) of Al_(y)Ga_((1-y))As)]

Composition-B: (GaAs, superlattice structure ofAl_(x2)Ga_((1-x2))As/Al_(x3)Ga_((1-x3))As, Al_(y)Ga_((1-y))As)

[0≦x2, x3≦1, x2≠x3, 0<y≦1, and (E_(g) of GaAs)<(E_(g-0) of superlatticestructure of Al_(x2)Ga_((1-x2))As/Al_(x3)Ga_((1-x3))As), (E_(g) ofsuperlattice structure ofAl_(x2)Ga_((1-x2))As/Al_(x3)Ga_((1-x3))As)≧(E_(g-1) ofAl_(y)Ga_((1-y))As)]

Furthermore, as long as energy band gap condition-A or energy band gapcondition-B is satisfied, when GaSb(As) or GaBi(As) is used as the III-Vcompound semiconductor of the substrate, the following composition canbe cited as Composition-A or Composition-B. Specifically, in thiscomposition, at least one layer of the compound semiconductor layerscontaining As (arsenic) contains Sb (antimony) or Bi (bismuth), whichhas an atomic radius larger than that of As and has a vapor pressurelower than that of As. Furthermore, the composition can also be cited inwhich, in at least one layer of the compound semiconductor layerscontaining As (arsenic), As is replaced by Sb (antimony) or Bi(bismuth), which has an atomic radius larger than that of As and has avapor pressure lower than that of As. As the combinations of (the III-Vcompound semiconductor of the substrate, the III-V compoundsemiconductor of the underlying layer, the III-V compound semiconductorof the first compound semiconductor layer) in the latter configuration,the following composition can be cited, as long as energy band gapcondition-A or energy band gap condition-B is satisfied.

Composition-C: (GaAs, {Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P,Al_(y)Ga_((1-y))As)

[0≦x4≦1, 0≦x5≦1, 0<y≦1, and (E_(g) of GaAs)<(E_(g-0) of{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P) (E_(g) of{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P)≧(E_(g-1) of Al_(y)Ga_((1-y))As)]

Furthermore, as long as energy band gap condition-A or energy band gapcondition-B is satisfied, when GaSb(As) or GaBi(As) is used as the III-Vcompound semiconductor of the substrate, the following composition canbe cited as Composition-C. Specifically, in this composition, at leastone layer of the compound semiconductor layers containing As (arsenic)contains Sb (antimony) or Bi (bismuth), which has an atomic radiuslarger than that of As and has a vapor pressure lower than that of As.Furthermore, the composition can also be cited in which, in at least onelayer of the compound semiconductor layers containing As (arsenic), Asis replaced by Sb (antimony) or Bi (bismuth), which has an atomic radiuslarger than that of As and has a vapor pressure lower than that of As.This feature applies also to a method for manufacturing a semiconductorlight emitting device according to a second mode of the presentinvention, to be described later.

In addition, as long as energy band gap condition-A or energy band gapcondition-B is satisfied, as the substrate, e.g. a GaN substrate, GaPsubstrate, AlN substrate, AlP substrate, InN substrate, InP substrate,AlGaInN substrate, AlGaN substrate, AlInN substrate, GaInN substrate,AlGaInP substrate, AlGaP substrate, AlInP substrate, GalnP substrate,and ZnS substrate can be cited, including the above-describedcompositions. In particular, it is preferable to use a substrate havinga zinc blende crystal structure or a substrate on which a crystal filmof the zinc blende crystal structure is formed. As atoms included in thesubstrate having the zinc blende crystal structure, at least As, Sb, andBi can be cited. In embodiments of the present invention, it is possibleto suppress light absorption of a substrate having high lightabsorbability to which the atoms of As, Sb, or Bi are added and hence inwhich the atoms are contained as a mixed crystal. As a result,enhancement and uniformization of the characteristics of thesemiconductor light emitting device can be achieved. Moreover, acomponent obtained by forming a buffer layer or an intermediate layer onthe surface (major surface) of any of the above-described substrates canbe used as the substrate. In crystal growth of the underlying layer withuse of any of these substrates, at least one of As, Sb, and Bi is addedas a group V material or used as a mixed crystal. This makes it easy toset a crystal growth condition under which the migration of group IIIatoms hardly occurs. Thus, it becomes possible to form a group V trimeron the outermost surface of the {111}B plane and thereby turn the {111}Bplane to a non-growth surface. Furthermore, as long as energy band gapcondition-A or energy band gap condition-B is satisfied, e.g. thefollowing materials can be cited as the materials of various compoundsemiconductor layers (the substrate, the underlying layer, the firstcompound semiconductor layer) including the active layer: GaInNAs-basedcompound semiconductors (including GaInAs-based mixed crystals andGaNAs-based mixed crystals), AlGaInP-based compound semiconductors,AlGaInAs-based compound semiconductors, GaInAs-based compoundsemiconductors, GaInAsP-based compound semiconductors, GalnP-basedcompound semiconductors, GaP-based compound semiconductors, andInP-based compound semiconductors.

According to the second mode of the present invention, there is provideda method for manufacturing a semiconductor light emitting device. Themethod includes the steps of:

(a) forming a plurality of mask layers extending along the <110>direction on the major surface of a substrate having the {100} plane asthe major surface, and exposing a part of the major surface of thesubstrate between the mask layers;

(b) epitaxially growing an underlying layer composed of a III-V compoundsemiconductor on the exposed part of the major surface of the substrate,and then removing the mask layers, the sectional shape of the underlyinglayer obtained when the underlying layer is cut along a virtual planeperpendicular to the <110> direction of the substrate being a trapezoid,the oblique surfaces of the underlying layer corresponding to twooblique sides of the trapezoid being the {111}B planes, and the topsurface of the underlying layer corresponding to the upper side of thetrapezoid being the {100} plane;

(c) forming, above the top surface of the underlying layer, a lightemitting part arising from sequential stacking of a first compoundsemiconductor layer of a first conductivity type, an active layer, and asecond compound semiconductor layer of a second conductivity type, andforming, on the exposed major surface of the substrate on which theunderlying layer is not formed, a multilayer structure arising fromsequential stacking of the first compound semiconductor layer of thefirst conductivity type, the active layer, and the second compoundsemiconductor layer of the second conductivity type; and

(d) forming, above the multilayer structure, a current block layer thatcovers at least the exposed side surface of the active layer of thelight emitting part.

In the method for manufacturing a semiconductor light emitting deviceaccording to the second mode of the present invention, it is desirableto use the underlying layer composed of a material having an energy bandgap (E_(g)) larger than the energy band gap (E_(g-0)) of the material ofthe substrate. That is, it is desirable to satisfy energy band gapcondition-A.

Furthermore, in the method for manufacturing a semiconductor lightemitting device according to the second mode of the present inventionincluding the above-described preferred mode, it is desirable to use theunderlying layer composed of a material having an energy band gap(E_(g)) larger than the energy band gap (E_(g-1)) of the material of thefirst compound semiconductor layer. That is, it is desirable to satisfyenergy band gap condition-B.

In the method for manufacturing a semiconductor light emitting deviceaccording to the second mode of the present invention including theabove-described various preferred modes, it is preferable that the III-Vcompound semiconductor of the underlying layer contain, as an element,at least one of arsenic (As), antimony (Sb), and bismuth (Bi), andaluminum (Al). Alternatively, it is preferable that the III-V compoundsemiconductor of the underlying layer contain at least phosphorus (P).The combinations of (the III-V compound semiconductor of the substrate,the III-V compound semiconductor of the underlying layer, the III-Vcompound semiconductor of the first compound semiconductor layer) are asdescribed above.

According to a third mode of the present invention, there is provided amethod for forming an underlying layer. The method includes the stepsof:

(a) forming a plurality of mask layers on the major surface of asubstrate, and exposing a part of the major surface of the substratebetween the mask layers; and

(b) epitaxially growing an underlying layer composed of a III-V compoundsemiconductor on the exposed part of the major surface of the substrate,and then removing the mask layers, wherein

an impurity whose substitution site is the site occupied by a group IIIatom and an impurity whose substitution site is the site occupied by agroup V atom are added to a material used for the epitaxial growth ofthe underlying layer of the n conductivity type in order to cause theunderlying layer to have the n conductivity type.

The method for forming an underlying layer according to the third modeof the present invention may have a mode in which the impurity whosesubstitution site is the site occupied by a group III atom is at leastone kind of impurity selected from the group composed of silicon and tinand the impurity whose substitution site is the site occupied by a groupV atom is at least one kind of impurity selected from the group composedof selenium, tellurium, and sulfur.

In the method for forming an underlying layer according to the thirdmode of the present invention including the above-described preferredmode, a configuration in which the substrate has the n conductivity typemay be employed.

Furthermore, the method for forming an underlying layer according to thethird mode of the present invention including the above-describedpreferred mode may have the following configuration. Specifically,

the substrate has the p conductivity type,

subsequently to the step (a), a base layer of the p conductivity type isepitaxially grown on the exposed part of the major surface of thesubstrate, and then in the step (b), the underlying layer composed ofthe III-V compound semiconductor is epitaxially grown on the base layerinstead of epitaxially growing the underlying layer composed of theIII-V compound semiconductor and having a single conductivity type onthe exposed part of the major surface of the substrate,

a tunnel junction is formed by the base layer and the underlying layer,and

at least around the interface between the base layer and the underlyinglayer and the vicinity of the interface, an impurity whose substitutionsite is the site occupied by a group III atom and an impurity whosesubstitution site is the site occupied by a group V atom are added to amaterial used for the epitaxial growth of the base layer of the pconductivity type in order to cause the base layer to have the pconductivity type. In particular, a tunnel junction formed of asuperlattice structure may be formed at least across the interfacebetween the base layer and the underlying layer and in the vicinity ofthe interface. In this case, for example, it is preferable that thefollowing configuration be employed at least in the tunnel junctionpart. Specifically,

the impurity whose substitution site is the site occupied by a group IIIatom in the base layer is at least one kind of impurity selected fromthe group composed of zinc, magnesium, beryllium, and manganese, and

the impurity whose substitution site is the site occupied by a group Vatom in the base layer is carbon. Furthermore, it is preferable toemploy the following configuration. Specifically,

the impurity whose substitution site is the site occupied by a group IIIatom in the underlying layer is at least one kind of impurity selectedfrom the group composed of silicon and tin, and

the impurity whose substitution site is the site occupied by a group Vatom in the underlying layer is at least one kind of impurity selectedfrom the group composed of selenium, tellurium, and sulfur.

As the condition under which the tunnel junction is formed by the baselayer and the underlying layer, the underlying layer having theconductivity type opposite to that of the substrate is joined onto thebase layer having the same conductivity type as that of the substrate.Furthermore, on the underlying layer, the first compound semiconductorlayer having the same conductivity type as that of the underlying layer,i.e. having the first conductivity type, is stacked. In addition, thelight emitting part arising from sequential stacking of the active layerand the second compound semiconductor layer of the second conductivitytype can be formed. With a mere pn junction, no current flows in thereverse direction basically. However, when a high voltage is applied inthe reverse direction, the depletion layer becomes very thin andelectrons tunnel through the depletion layer, so that current flowstarts. This is referred to as the Zener breakdown of a diode, and sucha diode is referred to as a Zener diode. The thickness of the depletionlayer can be further adjusted depending on the impurity concentration.Therefore, in this case, for example, if the junction is so made thatthe respective impurity concentrations of the interface junction partbetween the base layer and the underlying layer and the vicinity thereofare set as high as possible without significantly deteriorating thecrystal quality (at carrier concentrations in the range of 1×10¹⁸/cm³ to1×10²¹/cm³), the width of the depletion layer formed across the junctioninterface is small, which easily allows the tunnel effect. Furthermore,the tunnel effect will occur more readily when the band gap of thesemiconductor is smaller. Therefore, the materials may be so selectedthat, at least in the interface junction structure part, one of theoutermost layer (top surface layer) of the base layer and the lowermostlayer of the underlying layer closest to the base layer has a smallenergy band gap while the other of the layers has a large energy bandgap. In addition, by using the compound semiconductor layer composed ofsuch a material as a superlattice layer partially (using a very thinlayer), the percentage of the material having the small energy band gapcan be suppressed to the minimum, which makes it possible to suppressthe absorption amount of light generated by the light emitting layer tothe minimum necessary. As above, by paying attention on the impurityconcentrations, energy band gaps, and thicknesses of the compoundsemiconductor layers around the interface between the base layer and theunderlying layer and the vicinity of the interface, a structure that canachieve both enhancement in the tunnel effect and suppression of thelight absorption amount can be obtained. This feature applies also to amethod for forming an underlying layer according to a fourth mode of thepresent invention, to be described below.

According to the fourth mode of the present invention, there is providedanother method for forming an underlying layer. The method includes thesteps of:

(a) forming a plurality of mask layers on the major surface of asubstrate, and exposing a part of the major surface of the substratebetween the mask layers; and

(b) epitaxially growing an underlying layer composed of a III-V compoundsemiconductor on the exposed part of the major surface of the substrate,and then removing the mask layers, wherein

an impurity whose substitution site is the site occupied by a group IIIatom and an impurity whose substitution site is the site occupied by agroup V atom are added to a material used for the epitaxial growth ofthe underlying layer of the p conductivity type in order to cause theunderlying layer to have the p conductivity type.

The method for forming an underlying layer according to the fourth modeof the present invention may have a mode in which the impurity whosesubstitution site is the site occupied by a group III atom is at leastone kind of impurity selected from the group composed of zinc,magnesium, beryllium, and manganese and the impurity whose substitutionsite is the site occupied by a group V atom is carbon.

In the method for forming an underlying layer according to the fourthmode of the present invention including the above-described preferredmode, a configuration in which the substrate has the p conductivity typemay be employed.

Furthermore, the method for forming an underlying layer according to thefourth mode of the present invention including the above-describedpreferred mode may have the following configuration. Specifically,

the substrate has the n conductivity type,

subsequently to the step (a), a base layer of the n conductivity type isepitaxially grown on the exposed part of the major surface of thesubstrate, and then in the step (b), the underlying layer composed ofthe III-V compound semiconductor is epitaxially grown on the base layerinstead of epitaxially growing the underlying layer composed of theIII-V compound semiconductor and having a single conductivity type onthe exposed part of the major surface of the substrate,

a tunnel junction is formed by the base layer and the underlying layer,and

at least around the interface between the base layer and the underlyinglayer and the vicinity of the interface, an impurity whose substitutionsite is the site occupied by a group III atom and an impurity whosesubstitution site is the site occupied by a group V atom are added to amaterial used for the epitaxial growth of the base layer of the nconductivity type in order to cause the base layer to have the nconductivity type. In particular, a tunnel junction formed of asuperlattice structure may be formed at least across the interfacebetween the base layer and the underlying layer and in the vicinity ofthe interface. In this case, for example, it is preferable that thefollowing configuration be employed at least in the tunnel junctionpart. Specifically,

the impurity whose substitution site is the site occupied by a group IIIatom in the base layer is at least one kind of impurity selected fromthe group composed of silicon and tin, and

the impurity whose substitution site is the site occupied by a group Vatom in the base layer is at least one kind of impurity selected fromthe group composed of selenium, tellurium, and sulfur. Furthermore, itis preferable to employ the following configuration. Specifically,

the impurity whose substitution site is the site occupied by a group IIIatom in the underlying layer is at least one kind of impurity selectedfrom the group composed of zinc, magnesium, beryllium, and manganese,and

the impurity whose substitution site is the site occupied by a group Vatom in the underlying layer is carbon.

In the semiconductor light emitting device and the method formanufacturing the same according to the first and second modes of thepresent invention, and in the methods for forming an underlying layeraccording to the third and fourth modes of the present invention, it isdesirable to satisfy energy band gap condition-A or energy band gapcondition-B as described above. The term “energy band gap” is notlimited to an energy band gap in the case in which the related compoundsemiconductor layer is a single layer, but refers to an energy band gapin a broad sense, encompassing also an effective energy band gapobtained in the case in which the related compound semiconductor layeris formed of a multilayer structure (e.g. a superlattice multilayerstructure composed of a compound semiconductor layer having a largeenergy band gap and a compound semiconductor layer having a small energyband gap, a quantum well multilayer structure, or the averagecomposition of a multilayer structure). Therefore, even when a compoundsemiconductor layer that is considered to absorb light originally if itis a single layer is combined with another compound semiconductor layerthat does not absorb light so as to be included in the underlying layer,this underlying layer can be used as the underlying layer in the modesof the present invention if it does not function as an absorbing layersubstantially.

In the following description, at least one kind of impurity selectedfrom the group composed of three kinds of impurities of selenium (Se),tellurium (Te), and sulfur (S) is referred to as a group VI impurity,for convenience. Furthermore, at least one kind of impurity selectedfrom the group composed of two kinds of impurities of silicon (Si) andtin (Sn) is referred to as a group IV impurity, for convenience.Moreover, at least one kind of impurity selected from the group composedof four kinds of impurities of zinc (Zn), magnesium (Mg), beryllium(Be), and manganese (Mn) is referred to as a group II impurity, forconvenience.

In the semiconductor light emitting device and the method formanufacturing the same according to the first and second modes of thepresent invention and the methods for forming an underlying layeraccording to the third and fourth modes of the present inventionincluding the above-described various preferred configurations and modes(hereinafter, they will be often referred to simply as the presentinvention generically), the following materials can be cited as thematerial of the underlying layer: semiconductor oxides and semiconductornitrides such as SiO₂, SiN, and SiON; refractory metals; refractorymetal oxides; and refractory metal nitrides. Examples of the method forforming the mask layers include physical vapor deposition (PVD) such assputtering and chemical vapor deposition (CVD). For the removal of themask layers, either wet etching or dry etching may be employed dependingon the material of the mask layers.

In the semiconductor light emitting device and the method formanufacturing the same as the present invention, a semiconductor laseror a light emitting diode (LED) can be cited as the semiconductor lightemitting device.

Examples of the method for epitaxially growing the underlying layer andthe method for forming (depositing) various kinds of compoundsemiconductor layers including the active layer in the present inventioninclude metal organic chemical vapor deposition (MOCVD, MOVPE), metalorganic molecular beam epitaxy (MOMBE), and hydride vapor phase epitaxy(HVPE), in which a halogen contributes to transportation and reaction.

In the semiconductor light emitting device and the method formanufacturing the same as the present invention, the underlying layer isformed for forming the light emitting part. This underlying layer isprovided on the substrate separately from the substrate. Thus, thematerial of the underlying layer can be so selected that light generatedby the active layer will not be absorbed by the underlying layer evenwhen the active layer having a desired width is formed above theunderlying layer having a small width and thus the distance from theactive layer to the underlying layer is small. As a result, theoccurrence of a problem that the light emission efficiency (the slopeefficiency, represented by “light output/injected current”) is decreasedcan be suppressed. The height of the light emitting part is also definedby the width of the underlying layer. However, because a desired heightcan be designed as the height of the underlying layer, the occurrence ofa problem that the current block layer can not be formed on the sidesurfaces of the active layer can also be suppressed.

Moreover, in the methods for forming an underlying layer as the presentinvention, to the material used for the epitaxial growth of theunderlying layer of the n conductivity type or the p conductivity type,both an impurity whose substitution site is the site occupied by a groupIII atom and an impurity whose substitution site is the site occupied bya group V atom are added in order to cause the underlying layer to havethe n conductivity type or the p conductivity type. This allows theconductivity type of the underlying layer to be surely the desiredconductivity type.

In general, e.g. in the case of an anode-common semiconductor lightemitting device, if the underlying layer of the p conductivity type withhigh concentration and large thickness is formed on the substrate of thep conductivity type, white turbidity will arise in the underlying layerand the crystal quality of the compound semiconductor layer of theunderlying layer will be significantly deteriorated, depending on thecondition. Consequently, the crystal quality of the first compoundsemiconductor layer and the light emitting layer stacked over such anunderlying layer will also be adversely affected. For such a case, thesubstrate having the conductivity type opposite to that of theunderlying layer is used and the base layer having the conductivity typeopposite to that of the underlying layer is epitaxially grown on thesubstrate. Thereby, the occurrence of the above-described problem can besurely avoided, and an anode-common semiconductor light emitting devicecan be realized similarly to the case of using a p-type substrate. Inaddition, a tunnel junction is formed by the underlying layer and thebase layer. Therefore, even when voltage is applied to the semiconductorlight emitting device with the same polarity as that of the related art,a tunnel current is generated and thus electric conduction arises due toapplication of a reverse bias to the tunnel junction interface. Thus, acurrent flows to the active layer of the semiconductor light emittingdevice, so that light emission is obtained. An actual tunnel junctionstructure may be e.g. n⁺ layer/(i layer (lightly-doped layer)/n layer asa so-called delta-doped layer)/p⁺ layer in order to enhance the tunneleffect performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic partial sectional view of a semiconductor lightemitting device according to a first embodiment of the presentinvention, and FIG. 1B is a schematic partial sectional view ofpartially-enlarged third compound semiconductor layer and fourthcompound semiconductor layer;

FIG. 2 is a schematic partial sectional view of a substrate and anunderlying layer;

FIGS. 3A and 3B are schematic partial sectional views of a substrate andso on, for explaining the semiconductor light emitting device, a methodfor manufacturing the same, and a method for forming an underlying layeraccording to the first embodiment;

FIG. 4 is a schematic partial sectional view of the substrate and so on,subsequent to FIG. 3B, for explaining the semiconductor light emittingdevice and the method for manufacturing the same according to the firstembodiment;

FIG. 5 is a schematic partial sectional view of the substrate and so on,subsequent to FIG. 4, for explaining the semiconductor light emittingdevice and the method for manufacturing the same according to the firstembodiment;

FIG. 6A is a schematic partial sectional view of a semiconductor lightemitting device according to a third embodiment of the presentinvention, and FIG. 6B is a schematic partial sectional view ofpartially-enlarged third compound semiconductor layer and fourthcompound semiconductor layer;

FIGS. 7A and 7B are conceptual diagrams of semiconductor light emittingdevices according to a fifth embodiment and a ninth embodiment,respectively, of the present invention;

FIGS. 8A and 8B are conceptual diagrams of semiconductor light emittingdevices according to a sixth embodiment and a tenth embodiment,respectively, of the present invention;

FIGS. 9A and 9B are conceptual diagrams of semiconductor light emittingdevices according to a seventh embodiment and an eleventh embodiment,respectively, of the present invention;

FIGS. 10A and 10B are conceptual diagrams of semiconductor lightemitting devices according to an eighth embodiment and a twelfthembodiment, respectively, of the present invention;

FIGS. 11A to 20B are conceptual diagrams of a semiconductor lightemitting device according to a thirteenth embodiment of the presentinvention;

FIGS. 21A and 21B are conceptual diagrams of a semiconductor lightemitting device according to a fourteenth embodiment of the presentinvention;

FIGS. 22A and 22B are conceptual diagrams of a semiconductor lightemitting device according to a fifteenth embodiment of the presentinvention;

FIGS. 23A and 23B are conceptual diagrams of a semiconductor lightemitting device according to a sixteenth embodiment of the presentinvention;

FIGS. 24A and 24B are conceptual diagrams of a semiconductor lightemitting device according to a seventeenth embodiment of the presentinvention;

FIGS. 25A and 25B are conceptual diagrams of a semiconductor lightemitting device according to an eighteenth embodiment of the presentinvention;

FIGS. 26A and 26B are conceptual diagrams of a semiconductor lightemitting device according to a nineteenth embodiment of the presentinvention;

FIGS. 27A and 27B are conceptual diagrams of a semiconductor lightemitting device according to a twentieth embodiment of the presentinvention;

FIGS. 28A and 28B are conceptual diagrams of a semiconductor lightemitting device according to a twenty-first embodiment of the presentinvention;

FIGS. 29A to 48B are conceptual diagrams of a semiconductor lightemitting device according to a twenty-second embodiment of the presentinvention;

FIG. 49 is a schematic partial sectional view of the center part of thesemiconductor light emitting device according to the fourteenthembodiment;

FIG. 50 is a schematic partial sectional view of both the end parts ofthe semiconductor light emitting device according to the fourteenthembodiment;

FIGS. 51A to 51C are enlarged schematic partial sectional views of thesemiconductor light emitting device according to the fourteenthembodiment;

FIG. 52 is a schematic partial sectional view of a substrate and so on(at both the end parts of the semiconductor light emitting device), forexplaining a method for manufacturing a semiconductor light emittingdevice according to the fourteenth embodiment;

FIG. 53 is a schematic partial sectional view of the substrate and so on(at both the end parts of the semiconductor light emitting device), forexplaining the method for manufacturing a semiconductor light emittingdevice according to the fourteenth embodiment;

FIG. 54 is a schematic partial sectional view of the substrate and so on(at both the end parts of the semiconductor light emitting device), forexplaining the method for manufacturing a semiconductor light emittingdevice according to the fourteenth embodiment;

FIG. 55 is a schematic partial sectional view of the center part of thesemiconductor light emitting device according to the sixteenthembodiment;

FIG. 56 is a schematic partial sectional view of both the end parts ofthe semiconductor light emitting device according to the sixteenthembodiment;

FIGS. 57A to 57C are enlarged schematic partial sectional views of thesemiconductor light emitting device according to the sixteenthembodiment;

FIGS. 58A and 58B are schematic partial sectional views of a substrateand so on, for explaining a problem in a related-art semiconductor lightemitting device;

FIGS. 59A and 59B are schematic partial sectional views of the substrateand so on, for explaining another problem in the related-artsemiconductor light emitting device;

FIG. 60A is a schematic partial sectional view of a substrate and so on,for explaining a related-art method for manufacturing a semiconductorlight emitting device, and FIG. 60B is a schematic plan view of aprojection part or an underlying layer for manufacturing a semiconductorlight emitting device having a flare-stripe structure;

FIG. 61 is a schematic partial sectional view of the substrate and so on(at the center part of the semiconductor light emitting device),subsequent to FIG. 60A, for explaining the method for manufacturing asemiconductor light emitting device having the flare-stripe structure;

FIG. 62 is a schematic partial sectional view of the substrate and so on(at both the end parts of the semiconductor light emitting device),subsequent to FIG. 60A, for explaining the method for manufacturing asemiconductor light emitting device having the flare-stripe structure;

FIG. 63 is a schematic partial sectional view of the substrate and so on(at the center part of the semiconductor light emitting device),subsequent to FIG. 61, for explaining the method for manufacturing asemiconductor light emitting device having the flare-stripe structure;and

FIG. 64 is a schematic partial sectional view of the substrate and so on(at both the end parts of the semiconductor light emitting device),subsequent to FIG. 62, for explaining the method for manufacturing asemiconductor light emitting device having the flare-stripe structure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below withreference to the accompanying drawings.

First Embodiment

A first embodiment of the present invention relates to the semiconductorlight emitting device and the method for manufacturing the sameaccording to the first and second modes of the present invention and themethod for forming an underlying layer according to the third mode ofthe present invention.

In the first embodiment, and second to twenty-second embodiments of thepresent invention, to be described later, selenium (Se) is used as atleast one kind of impurity selected from the group composed of selenium(Se), tellurium (Te), and sulfur (S) (group VI impurity). Furthermore,silicon (Si) is used as at least one kind of impurity selected from thegroup composed of silicon (Si) and tin (Sn) (group IV impurity). Inaddition, zinc (Zn) is used as at least one kind of impurity selectedfrom the group composed of zinc (Zn), magnesium (Mg), beryllium (Be),and manganese (Mn) (group II impurity). However, the present inventionis not limited to these impurities.

The semiconductor light emitting devices in the first embodiment and thesecond to twenty-second embodiments to be described later are formed ofa semiconductor laser, and specifically an SDH semiconductor laser.

A schematic partial sectional view of the semiconductor light emittingdevice of the first embodiment is shown in FIG. 1A, and a schematicpartial sectional view of a substrate and an underlying layer is shownin FIG. 2. The semiconductor light emitting device of the firstembodiment includes:

(A) an underlying layer 11 that is formed on the major surface of asubstrate 10 having the {100} plane as the major surface;

(B) a light emitting part 20 that arises from sequential stacking of afirst compound semiconductor layer 21 of a first conductivity type(n-type, in the first embodiment), an active layer 23, and a secondcompound semiconductor layer 22 of a second conductivity type (p-type,in the first embodiment) above the top surface of the underlying layer11; and

(C) a current block layer 40 that is formed above a part of the majorsurface of the substrate 10 on which the underlying layer 11 is notformed (this part will be often referred to as the exposed surface ofthe substrate 10) and covers at least the exposed side surface of theactive layer 23 of the light emitting part 20.

The underlying layer 11 is composed of a III-V compound semiconductorand is formed on the major surface of the substrate 10 by epitaxialgrowth. The underlying layer 11 extends in parallel to the <110>direction of the substrate 10. The sectional shape of the underlyinglayer 11 obtained when the underlying layer 11 is cut along a virtualplane perpendicular to the <110> direction of the substrate 10 is atrapezoid. The oblique surfaces of the underlying layer 11 correspondingto two oblique sides of this trapezoid are the {111}B planes, and thetop surface of the underlying layer 11 corresponding to the upper sideof the trapezoid is the {100} plane. That is, the underlying layer 11has a so-called mesa structure and extends along the [011] direction.

Specifically, in the first embodiment, the substrate 10 is composed ofn-GaAs, and the III-V compound semiconductor of the underlying layer 11contains as its elements at least one of arsenic (As), antimony (Sb),and bismuth (Bi), and aluminum (Al). More specifically, the underlyinglayer 11 is composed of e.g. n-Al_(x1)Ga_((1-x1))As:Se [0<x1≦1,specifically, e.g. x1=0.1, 0.2, 0.3, 0.4, or 0.47], and the firstcompound semiconductor layer 21 is composed of n-Al_(0.4)Ga_(0.6)As:Se.Therefore, the energy band gap (E_(g)) of the material of the underlyinglayer 11 is larger than the energy band gap (E_(g-0)) of the material ofthe substrate 10. Furthermore, the energy band gap (E_(g)) of thematerial of the underlying layer 11 is larger than the energy band gap(E_(g-1)) of the material of the first compound semiconductor layer 21.The current block layer 40 is composed of a third compound semiconductorlayer 43 of the first conductivity type (n-type) and a fourth compoundsemiconductor layer 44 of the second conductivity type (p-type) incontact with the third compound semiconductor layer 43. Forsimplification, in the drawings, two or more layers that have the sameconductivity type and the same impurity site but have differentrefractive indexes (e.g. in the case of two layers, a second compoundsemiconductor layer 22A and a second compound semiconductor layer 22B)are collectively represented as one layer (the second compoundsemiconductor layer 22). FIG. 1B is a schematic partial sectional viewof the partially-enlarged third compound semiconductor layer 43 andfourth compound semiconductor layer 44. Details will be described laterabout the compositions of the respective compound semiconductor layersincluded in the light emitting part 20 and the compositions of therespective compound semiconductor layers included in the current blocklayer 40 in the semiconductor light emitting device of the firstembodiment.

In the semiconductor light emitting device of the first embodiment,above the top surface of the underlying layer 11 provided on thesubstrate 10, a buffer layer 12 composed of GaAs of the firstconductivity type, the first compound semiconductor layer 21, the activelayer 23, and the second compound semiconductor layer 22A aresequentially formed. Furthermore, the second compound semiconductorlayer 22B is formed on the second compound semiconductor layer 22A, sothat the apex is formed. The sectional shape of the light emitting part20 including the second compound semiconductor layer 22B, obtained whenthe underlying layer 11 is cut along the {011}A plane, is a triangle.The side surfaces of the light emitting part 20 are the {111}B planes(specifically, the (11-1)B plane and the (1-11)B plane). By controllingthe compositions of the second compound semiconductor layer 22A and thesecond compound semiconductor layer 22B, the light emitting part 20having a triangular sectional shape can be accurately formed. Ingeneral, the {111}B plane is known as a non-growth surface covered by anAs trimer in MOCVD (referred to also as MOVPE), except for specialcrystal growth conditions. Therefore, in the case of an SDHsemiconductor laser, after the light emitting part 20 whose obliquesurface (side surface) is the {111}B plane is formed, “self growth stop”of the crystal growth of the light emitting part is kept even if theMOCVD is continued thereafter. The angle of the {111}B plane is 54.7degrees. Depending on the growth condition and so on, it is alsopossible that the part having a triangular sectional shape be composedonly of the light emitting part 20.

On the other hand, over the part of the {100} plane (the (100) plane, inthe illustrated example) as the exposed surface (major surface) of thesubstrate 10, the following components are sequentially formed: the samestructure as that of the light emitting part 20; a layer 30 foradjustment of the current block layer position (hereinafter, referred tosimply as the adjustment layer 30, and the adjustment layer 30 is acontinuation part of the second compound semiconductor layer 22substantially); the current block layer 40; and a burying layer (cladlayer for burying) 31.

Furthermore, the whole device is covered by the contact layer (caplayer) 32 that is composed of GaAs of the second conductivity type. Inaddition, the first electrode 51 is formed on the backside of thesubstrate 10, and the second electrode 52 is formed on the contact layer(cap layer) 32.

A method for manufacturing a semiconductor light emitting device and amethod for forming an underlying layer according to the first embodimentwill be described below.

[Step-100]

Initially, plural mask layers 11A extending along the <110> directionare formed on the major surface of the substrate 10 having the {100}plane as the major surface, and a part of the major surface of thesubstrate 10 is exposed between the mask layers 11A. Alternatively, theplural mask layers 11A are formed on the major surface of the substrate10, and a part of the major surface of the substrate 10 is exposedbetween the mask layers 11A. Specifically, on the {100} crystal plane,e.g. the (100) crystal plane, of the substrate 10 composed of n-GaAs asits major surface, the mask layers 11A that are composed of SiO₂ andextend along the [011]A direction are formed based on CVD and aphotolithography technique (see FIG. 3A).

[Step-110]

Subsequently, the underlying layer 11 that is composed of a III-Vcompound semiconductor and has the following feature is epitaxiallygrown on the exposed part of the major surface of the substrate 10.Specifically, the sectional shape of the underlying layer 11 obtainedwhen the underlying layer 11 is cut along a virtual plane perpendicularto the <110> direction of the substrate 10 is a trapezoid. Furthermore,the oblique surfaces of the underlying layer 11 corresponding to twooblique sides of this trapezoid are the {111}B planes, and the topsurface of the underlying layer 11 corresponding to the upper side ofthe trapezoid is the {100} plane. Subsequently to the epitaxial growthof the underlying layer 11, the mask layers 11A are removed.Alternatively, the underlying layer 11 composed of a III-V compoundsemiconductor is epitaxially grown on the exposed part of the majorsurface of the substrate 10, and then the mask layers 11A are removed.To the material used for the epitaxial growth of the underlying layer 11having the n conductivity type, an impurity whose substitution site isthe site occupied by a group III atom and an impurity whose substitutionsite is the site occupied by a group V atom are added in order to causethe underlying layer 11 to have the n conductivity type.

Specifically, for example, trimethylaluminum (TMAl) or triethylaluminum(TEAl) is used as the material gas of the aluminum (Al) source, andtrimethylgallium (TMGa) or triethylgallium (TEGa) is used as thematerial gas of the gallium (Ga) source. In addition, tertiary butylarsine (TBAs) or arsine (AsH₃) is used as the material gas of thearsenic (As) source. Furthermore, as the gas for n-type impurity doping,disilane (Si₂H₆), monosilane (SiH₄), or trimethyltin (TMSn) is used, ifthe site to be substituted by the impurity is the group III site. Inaddition, as the gas for n-type impurity doping, hydrogen sulfide (H₂S),hydrogen selenide (H₂Se), or hydrogen telluride (H₂Te) is used, if thesite to be substituted by the impurity is the group V site. Based onMOCVD, these group III gas, group V gas, and impurity gas are introducedinto a reaction chamber and subjected to a pyrolytic reaction in atemperature range of 600° C. to 900° C. for high-temperature growth.This promotes the migration of the group III material, and thus allowsthe epitaxial growth of a compound semiconductor layer having highflatness of the {100} plane and high crystal quality. Furthermore, dueto this MOCVD, it is possible to form the underlying layer 11 that isformed of an AlGaAs-based material layer whose energy band gap is largerthan at least that of the GaAs substrate and has a trapezoidal shapewith desired top-surface width and height.

In order to further improve the flatness of the top surface of theunderlying layer 11, a growth condition that permits promotion of themigration of the group III material may be employed through adjustmentto a high flow rate of the supply gas to be introduced into the reactionchamber and adjustment to a low mole supply ratio of (group Vgas)/(group III gas). Furthermore, in order to increase theconcentration of the n-type impurity in the underlying layer 11, theautodoping amount of carbon (C) arising from methyl groups (CH₃—), ethylgroups (C₂H₅—), and tertiary butyl groups ((CH₃)₃C—) contained in thesupplied material (organic metal) gas (i.e., the amount of formation ofholes (p conductivity type layer) through substitution for the group Vsite) may be decreased. For this purpose, for the substitution for thegroup V site in the formation of the n conductivity type layer, acondition may be aggressively used under which carbon (C) arising frommethyl groups (CH₃—), ethyl groups (C₂H₅—), and tertiary butyl groups((CH₃)₃C—) competes with an n-type impurity that can substitute for thegroup V site. Specifically, the ratio to carbon may be relativelyincreased. More specifically, the mole supply ratio of the n-typeimpurity material gas (e.g. H₂S, H₂Se, or H₂Te) to carbon (C) may beincreased. In addition, to decrease the absolute amount of carbon (C)itself, e.g. the Al mole fraction of the AlGaAs-based underlying layer11 (the gas supply amount of TMAl) may be decreased without permittingthe underlying layer 11 to absorb light generated by the light emittinglayer, to thereby reduce the capturing of carbon (C). This is because ofthe following reason. Specifically, in general, e.g. TMAl forms a dimerat the time of the growth of the AlGaAs-based underlying layer 11, andthus methyl groups (CH₃—) and ethyl groups (C₂H₅—) are also easilycaptured in the crystal together with Al. Therefore, by decreasing theAl mole fraction of the AlGaAs-based underlying layer 11, the capturingof carbon (C) can be reduced, and hence the autodoping amount can bedecreased.

In this manner, the underlying layer 11 extending along the [011]Adirection can be obtained (see FIG. 3B). The underlying layer 11 isdeposited not on the mask layers 11A but on the major surface of thesubstrate 10. The width direction of the underlying layer 11 is parallelto the [0-11]B direction. Thereafter, the mask layers 11A composed ofSiO₂ are removed based on wet etching. In this Way, the structure shownin FIG. 2 can be obtained. The underlying layer 11 has the obliquesurfaces (side surfaces) formed of the (11-1)B plane and the (1-11)Bplane, and the top surface of the underlying layer 11 is the (100)plane. The obtained underlying layer 11 contains, as impurities,selenium (impurity whose substitution site is the site occupied by agroup V atom) and silicon (impurity whose substitution site is the siteoccupied by a group III atom) for causing the underlying layer 11 to bethe n-type.

[Step-120]

Thereafter, above the top surface of the underlying layer 11, the lightemitting part 20 arising from sequential stacking of the first compoundsemiconductor layer 21 of the first conductivity type, the active layer23, and the second compound semiconductor layer 22 of the secondconductivity type is formed. In addition, on the exposed major surfaceof the substrate 10 on which the underlying layer 11 is not formed (theexposed surface of the substrate 10), a multilayer structure arisingfrom sequential stacking of the first compound semiconductor layer 21 ofthe first conductivity type, the active layer 23, and the secondcompound semiconductor layer 22 of the second conductivity type isformed. Specifically, based on normal MOCVD, i.e., MOCVD with use of anorganic metal and a hydrogen compound as the material gas, the bufferlayer 12, the first compound semiconductor layer 21, the active layer23, and the second compound semiconductor layers 22A and 22B areepitaxially grown over the underlying layer 11 and the exposed surfaceof the substrate 10. At this time, the oblique surfaces (side surfaces)of the compound semiconductor layers above the underlying layer 11correspond to the {111}B plane. As described above, the {111}B plane isa non-growth surface. Therefore, the buffer layer 12, the first compoundsemiconductor layer 21, the active layer 23, and the second compoundsemiconductor layers 22A and 22B are so formed (stacked) that the layersin the region above the underlying layer 11 are separated from those inthe region above the exposed surface of the substrate 10. In this Way,the structure shown in FIG. 4 can be obtained.

By properly selecting the width of the top surface of the underlyinglayer 11 and the height of the underlying layer 11 and properlyselecting the thicknesses of the buffer layer 12, the first compoundsemiconductor layer 21, the active layer 23, and the second compoundsemiconductor layers 22A and 22B, the multilayer structure of the lightemitting part 20 having a triangular sectional shape can be obtainedabove the underlying layer 11.

As an alternative, the following configuration may be employed.Specifically, the substrate 10 is composed of p-GaAs. Furthermore,subsequently to [Step-100], on the exposed part of the major surface ofthe substrate 10, a base layer of the p conductivity type (specifically,a p-Al_(x1)Ga_((1-x1))As layer [0≦x1≦1], and in particular, ap⁺⁺-Al_(x1)Ga_((1-x1))As layer [0<x1≦1] or a superlattice layer formedof a p⁺⁺-GaAs layer may be used at the uppermost part (top surface part)of the p-type base layer closest to the underlying layer) is epitaxiallygrown. Subsequently, in [Step-110], the underlying layer 11 composed ofthe above-described III-V compound semiconductor is epitaxially grown onthe base layer. In this configuration, a tunnel junction is formed bythe base layer and the underlying layer 11. In the case of a mere pnjunction (the pn junction between the base layer and the underlyinglayer), current flowing in the reverse direction attributed to thetunnel effect will not occur basically. However, the thickness of thedepletion layer can be further adjusted depending on the impurityconcentration for example. Therefore, in order to cause the tunneleffect, the impurity concentrations of the respective layers in theregion around the junction interface may be set as high as possiblewithout significantly deteriorating the crystal quality. This decreasesthe width of the depletion layer formed across the junction interface.Thus, the tunnel effect is readily caused when a reverse bias isapplied. Furthermore, the tunnel effect will occur more readily when theband gap of the semiconductor is smaller. Therefore, the materials maybe so selected that, at least in the interface junction structure part,one of the outermost layer (top surface layer) of the base layer and thelowermost layer of the underlying layer closest to the base layer has asmall energy band gap while the other of the layers has a large energyband gap. In addition, by using this compound semiconductor layer as asuperlattice layer partially (using a very thin layer), the percentageof the material having the small energy band gap can be suppressed tothe minimum, which makes it possible to suppress the absorption amountof light generated by the light emitting layer to the minimum necessary.In this manner, a condition with attention on the impurityconcentrations, energy band gaps, and thicknesses of the compoundsemiconductor layers that form the interface between the base layer andthe underlying layer and are in the vicinity of the interface may beemployed.

At least around the interface between the base layer and the underlyinglayer and the vicinity of the interface, an impurity whose substitutionsite is the site occupied by a group III atom and an impurity whosesubstitution site is the site occupied by a group V atom are added tothe material used for the epitaxial growth of the base layer having thep conductivity type in order to cause the base layer to have the pconductivity type. Specifically, as the material used for the epitaxialgrowth of the base layer, for example, trimethylaluminum (TMAl) ortriethylaluminum (TEAl) is used as the material gas of the aluminum (Al)source, and trimethylgallium (TMGa) or triethylgallium (TEGa) is used asthe material gas of the gallium (Ga) source. In addition, tertiary butylarsine (TBAs) or arsine (AsH₃) is used as the material gas of thearsenic (As) source. Furthermore, as the gas for p-type impurity doping,e.g. trimethylzinc (TMZn), triethylzinc (TEZn), biscyclopentadienylmagnesium (Cp₂Mg), bisethylcyclopentadienyl magnesium (EtCp₂Mg),bisisopropylcyclopentadienyl magnesium (i-PrCp₂Mg),bismethylcyclopentadienyl magnesium (MeCp₂Mg), or trimethylmanganese(TMMn) is used, if the site to be substituted by the impurity is thegroup III site. In addition, as the gas for p-type impurity doping,carbon tetrachloride (CCl₄), carbon tetrabromide (CBr₄), carbontetraiodide (CI₄), or the like is used as the material gas of the carbon(C) source, if the site to be substituted by the impurity is the group Vsite. Moreover, as another carbon (C) source, a growth condition may beemployed under which methyl groups and ethyl groups contained in e.g.the material gases (organic metal gases) of the Al source, the Gasource, and the As source are aggressively captured in the crystal (usedfor autodoping). In particular, for the tunnel junction part formed bythe p-type base layer and the n-type underlying layer and the vicinitythereof, the base layer formed of a p⁺⁺-type layer (heavily-doped layer)and the n⁺⁺-type underlying layer should be used. Therefore, it isimportant that, as the gases for the impurity doping for the p⁺⁺-typebase layer, at least two kinds of gases by which the group III site andthe group V site are to be substituted by impurities be used for thesame layer.

[Step-130]

Thereafter, over the multilayer structure, the current block layer 40that covers at least the exposed side surfaces of the active layer 23 ofthe light emitting part 20 is formed. Specifically, continuously to theformation of the second compound semiconductor layer 22B, the adjustmentlayer 30 is formed across the entire surface based on MOCVD.Furthermore, the current block layer 40 composed of e.g. the fourthcompound semiconductor layer 44 and the third compound semiconductorlayer 43 is formed based on MOCVD (see FIG. 5). The current block layer40 is not grown on the {111}B plane. The current block layer 40 is soformed that the end surfaces of the current block layer 40 cover atleast the side surfaces of the active layer 23. Such configuration andstructure can be achieved by properly selecting the width of the topsurface of the underlying layer 11, the height of the underlying layer11, and the thickness of the adjustment layer 30. Details of theconfigurations and structures of the third compound semiconductor layer43 and the fourth compound semiconductor layer 44 will be describedlater.

[Step-140]

Subsequently, the burying layer 31 and the contact layer (cap layer) 32are sequentially formed across the entire surface based on MOCVD.Specifically, due to the continuation of the MOCVD, the burying layer 31formed of the compound semiconductor arising from the crystal growthfrom the exposed surface of the substrate 10 will in time completelycover the light emitting part 20 in the self growth stop state.Thereafter, the second electrode 52 is formed on the contact layer 32based on vacuum evaporation. Furthermore, the substrate 10 is lapped toa proper thickness from the backside thereof, and then the firstelectrode 51 is formed based on vacuum evaporation.

[Step-150]

Thereafter, the respective semiconductor light emitting devices areseparated from each other, so that the desired semiconductor lightemitting devices can be obtained. The semiconductor light emittingdevices of the second to thirteenth embodiments to be described latercan also be manufactured based on a method similar to theabove-described method basically.

In the first embodiment, the underlying layer 11 is formed for formingthe light emitting part 20. This underlying layer 11 is provided on thesubstrate 10 separately from the substrate 10. Thus, even when theactive layer 23 having a desired width is formed above the underlyinglayer 11 having a small width and thus the distance from the activelayer 23 to the underlying layer 11 is small, the material of theunderlying layer 11 can be so selected that light generated by theactive layer 23 will not be absorbed by the underlying layer 11. As aresult, the occurrence of a problem that the light emission efficiency(slope efficiency) is decreased can be suppressed. The height of thelight emitting part 20 is also defined by the width of the underlyinglayer 11, and the predetermined range exists regarding the aspect ratio(e.g. the value of “height/width”) of the underlying layer 11corresponding to the desired width of the active layer 23. Thus, inorder to allow the formation of the current block layer 40 on the sidesurfaces of the active layer 23, the aspect ratio should be set withinthis range. If the width of the apertures of the mask layers 11A (thewindows of the mask layers 11A) is designed also in consideration of thecharacteristic that the angle formed by the {111}B plane as the sidesurface (trapezoid oblique surface) of the underlying layer 11 and the{100} plane is constant (54.7 degrees), the top-surface width and aspectratio of the underlying layer 11 can be simultaneously controlleddepending on the time of the epitaxial growth of the underlying layer11. In a related art, a recess-and-projection substrate obtained throughsubstrate etching (etching involving control fluctuation) involvesvariation in the width and height of the projection part, i.e., in theaspect ratio of the projection part, in the substrate and further in theaperture of one mask layer 11A. This results in the occurrence of aproblem that, in a partial region of the substrate, the current blocklayer can not be formed on the side surfaces of the active layer in thelight emitting part formed above the top surface of the underlying layer11. In contrast, in the first embodiment, the desired aspect ratio ofthe underlying layer 11 corresponding to the desired width of the activelayer 23 can be controlled depending on the design of the mask layers11A and the time of the epitaxial growth of the underlying layer 11.This allows not only improvement to high carrier concentration but alsogreat improvement in the in-plane flatness of the recess-and-projectionstructure in the substrate. Moreover, in the method for forming anunderlying layer according to the first embodiment, an impurity whosesubstitution site is the site occupied by a group III atom and animpurity whose substitution site is the site occupied by a group V atomare added to the material used for the epitaxial growth of theunderlying layer 11 having the n conductivity type in order to cause theunderlying layer 11 to have the n conductivity type. This allows theconductivity type of the underlying layer 11 to be surely the nconductivity type.

Second Embodiment

The second embodiment is a modification of the first embodiment. In thesecond embodiment, the III-V compound semiconductor of the underlyinglayer 11 contains at least phosphorus (P) as its element. Morespecifically, the underlying layer 11 is composed of e.g.n-{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P:Se [0≦x4≦1, x5=0.5,specifically, e.g. x4=0, 0.1, 0.2, 0.3, or 1], which readily achieveslattice matching with the substrate composed of GaAs, and the firstcompound semiconductor layer 21 is composed of n-Al_(0.4)Ga_(0.6)As:Se.Therefore, the energy band gap (E_(g)) of the material of the underlyinglayer 11 is larger than the energy band gap (E_(g-0)) of the material ofthe substrate 10. Furthermore, the energy band gap (E_(g)) of thematerial of the underlying layer 11 is larger than the energy band gap(E_(g-1)) of the material of the first compound semiconductor layer 21.

In a method for manufacturing a semiconductor light emitting device anda method for forming an underlying layer according to the secondembodiment, in a step similar to [Step-110] of the first embodiment,e.g. trimethylaluminum (TMAl) or triethylaluminum (TEAl) is used as thematerial gas of the aluminum (Al) source, and trimethylgallium (TMGa) ortriethylgallium (TEGa) is used as the material gas of the gallium (Ga)source. In addition, trimethylindium (TMIn) or triethylindium (TEIn) isused as the material gas of the indium (In) source, and tertiary butylphosphine (TBP) or phosphine (PH₃) is used as the material gas of thephosphorus (P) source. Furthermore, as the gas for n-type impuritydoping, disilane (Si₂H₆), monosilane (SiH₄), or trimethyltin (TMSn) isused, if the site to be substituted by the impurity is the group IIIsite. In addition, as the gas for n-type impurity doping, hydrogensulfide (H₂S), hydrogen selenide (H₂Se), or hydrogen telluride (H₂Te) isused, if the site to be substituted by the impurity is the group V site.Based on MOCVD, these group III gas, group V gas, and impurity gas areintroduced into a reaction chamber and subjected to a pyrolytic reactionin a temperature range of 600° C. to 900° C. for high-temperaturegrowth. This promotes the migration of the group III material, and thusallows the epitaxial growth of a compound semiconductor layer havinghigh flatness of the {100} plane and high crystal quality. Furthermore,due to this MOCVD, it is possible to form the underlying layer 11 thatis formed of an AlGaAs-based material layer whose energy band gap islarger than at least that of the GaAs substrate and has a trapezoidalshape with desired top-surface width and height.

In order to further improve the flatness of the top surface of theunderlying layer 11, a growth condition that permits promotion of themigration of the group III material may be employed through adjustmentto a high flow rate of the supply gas to be introduced into the reactionchamber and adjustment to a low mole supply ratio of (group Vgas)/(group III gas). The material characteristic of the AlGaInP-basedmaterial is such that the {111}B plane (side surface) of the underlyinglayer 11 formed by using the AlGaInP-based material (containing no As)grows greatly readily compared with the {111}B plane (side surface) ofthe underlying layer 11 formed by using the AlGaAs-based material(containing As) (the range of the condition under which the {111}B planegrows is greatly wider in the case of the AlGaInP-based material).Therefore, selection of the material gas of the phosphorus (P) source isimportant for widening of the control range of the {111}B plane (sidesurface) growth of the AlGaInP-based material (e.g. for realization ofthe turning of the {111}B plane (side surface) to a non-growth surface).As this selection, it is desirable to use tertiary butyl phosphine(TBP), which is excellent in the low-temperature decompositionefficiency. By using such a group V material gas with highlow-temperature decomposition efficiency, even with a smaller molesupply amount of the material gas compared with that of phosphine (PH₃),whose decomposition efficiency is low, the same effective mole supplyratio of group V/group III can be realized at the time of pyrolysis.Therefore, when the gas mole supply amount is the same, tertiary butylphosphine (TBP) is advantageous over phosphine (PH₃) in terms of thefollowing feature. Specifically, using tertiary butyl phosphine (TBP)allows, only through wide-range flow rate adjustment by a mass flowcontroller (MFC), changing in the condition range in which the effectivemole supply ratio of group V/group III is high for a wide temperaturerange from a temperature for low-temperature growth to a temperature forhigh-temperature growth. This makes it possible to variously treat thecontrol of the crystal planes of the underlying layer 11 (e.g. theflatness of the {100} plane and the degree of the growth of the {111}Bplane). Because the present case relates to an example of the material“containing no As,” the description thereof is made with use of tertiarybutyl phosphine (TBP) as the material gas having excellentcharacteristics. However, it is obvious that, in the case of an exampleof the material “containing As,” the description can be made with use oftertiary butyl arsine (TBAs) as the material gas having excellentcharacteristics similarly.

Except for the above-described features, the semiconductor lightemitting device, the method for manufacturing the same, and the methodfor forming an underlying layer according to the second embodiment canbe considered the same as those according to the first embodiment.Therefore, the detailed description thereof is omitted.

As an alternative, the following configuration may be employed.Specifically, the substrate 10 is composed of p-GaAs. Furthermore,subsequently to the step similar to [Step-100], on the exposed part ofthe major surface of the substrate 10, a base layer of the pconductivity type (specifically, ap-{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P layer [0≦x4≦1, x5=0.5], and inparticular, a p⁺⁺-{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P layer [0≦x4≦1,x5=0.5] or a superlattice layer formed of a p⁺⁺-GaAs layer may be usedat the uppermost part (top surface part) of the p-type base layerclosest to the underlying layer) is epitaxially grown. Subsequently, inthe step similar to [Step-110], the underlying layer 11 composed of theabove-described III-V compound semiconductor is epitaxially grown on thebase layer. In this configuration, a tunnel junction is formed by thebase layer and the underlying layer 11. In the case of a mere pnjunction (the pn junction between the base layer and the underlyinglayer), current flowing in the reverse direction attributed to thetunnel effect will not occur basically. However, the thickness of thedepletion layer can be further adjusted depending on the impurityconcentration for example. Therefore, in order to cause the tunneleffect, the impurity concentrations of the respective layers in theregion around the junction interface may be set as high as possiblewithout significantly deteriorating the crystal quality. This decreasesthe width of the depletion layer formed across the junction interface.Thus, the tunnel effect is readily caused when a reverse bias isapplied. Furthermore, the tunnel effect will occur more readily when theband gap of the semiconductor is smaller. Therefore, the materials maybe so selected that, at least in the interface junction structure part,one of the outermost layer (top surface layer) of the base layer and thelowermost layer of the underlying layer closest to the base layer has asmall energy band gap while the other of the layers has a large energyband gap. In addition, by using this compound semiconductor layer as asuperlattice layer partially (using a very thin layer), the percentageof the material having the small energy band gap can be suppressed tothe minimum, which makes it possible to suppress the absorption amountof light generated by the light emitting layer to the minimum necessary.In this manner, a condition with attention on the impurityconcentrations, energy band gaps, and thicknesses of the compoundsemiconductor layers that form the interface between the base layer andthe underlying layer and are in the vicinity of the interface may beemployed.

At least around the interface between the base layer and the underlyinglayer and the vicinity of the interface, an impurity whose substitutionsite is the site occupied by a group III atom and an impurity whosesubstitution site is the site occupied by a group V atom are added tothe material used for the epitaxial growth of the base layer having thep conductivity type in order to cause the base layer to have the pconductivity type. Specifically, as the material used for the epitaxialgrowth of the base layer, for example, trimethylaluminum (TMAl) ortriethylaluminum (TEAl) is used as the material gas of the aluminum (Al)source, and trimethylgallium (TMGa) or triethylgallium (TEGa) is used asthe material gas of the gallium (Ga) source. Furthermore,trimethylindium (TMIn) or triethylindium (TEIn) is used as the materialgas of the indium (In) source, and tertiary butyl phosphine (TBP) orphosphine (PH₃) is used as the material gas of the phosphorus (P)source. In addition, tertiary butyl arsine (TBAs) or arsine (AsH₃) isused as the material gas of the arsenic (As) source. Furthermore, as thegas for p-type impurity doping, e.g. trimethylzinc (TMZn), triethylzinc(TEZn), biscyclopentadienyl magnesium (Cp₂Mg), bisethylcyclopentadienylmagnesium (EtCp₂Mg), bisisopropylcyclopentadienyl magnesium (i-PrCp₂Mg),bismethylcyclopentadienyl magnesium (MeCp₂Mg), or trimethylmanganese(TMMn) is used, if the site to be substituted by the impurity is thegroup III site. In addition, as the gas for p-type impurity doping,carbon tetrachloride (CCl₄), carbon tetrabromide (CBr₄), carbontetraiodide (CI₄), or the like is used as the material gas of the carbon(C) source, if the site to be substituted by the impurity is the group Vsite. Moreover, as another carbon (C) source, a growth condition may beemployed under which methyl groups and ethyl groups contained in e.g.the material gases (organic metal gases) of the Al source, the Gasource, and the As source are aggressively captured in the crystal (usedfor autodoping). In particular, for the tunnel junction part formed bythe p-type base layer and the n-type underlying layer and the vicinitythereof, the base layer formed of a p⁺⁺-type layer (heavily-doped layer)and the n⁺⁺-type underlying layer should be used. Therefore, it isimportant that, as the gases for the impurity doping for the p⁺⁺-typebase layer, at least two kinds of gases by which the group III site andthe group V site are to be substituted by impurities be used for thesame layer.

Third Embodiment

The third embodiment is a modification of the semiconductor lightemitting device and the method for manufacturing the same according tothe first embodiment, and relates to the method for forming anunderlying layer according to the fourth mode of the present invention.

A schematic partial sectional view of the semiconductor light emittingdevice of the third embodiment is shown in FIG. 6A. A schematic partialsectional view of the substrate and the underlying layer in thissemiconductor light emitting device is similar to that shown in FIG. 2.The semiconductor light emitting device of the third embodiment has thesame structure as that of the semiconductor light emitting device of thefirst embodiment, except that the conductivity types of a part of thecompound semiconductor layers are different from those in thesemiconductor light emitting device of the first embodiment.

Specifically, the semiconductor light emitting device of the thirdembodiment includes:

(A) an underlying layer 11 that is formed on the major surface of asubstrate 10 having the {100} plane as the major surface;

(B) a light emitting part 20 that arises from sequential stacking of afirst compound semiconductor layer 21 of a first conductivity type(p-type, in the third embodiment), an active layer 23, and a secondcompound semiconductor layer 22 of a second conductivity type (n-type,in the third embodiment) above the top surface of the underlying layer11; and

(C) a current block layer 40 that is formed above a part of the majorsurface of the substrate 10 on which the underlying layer 11 is notformed (the exposed surface of the substrate 10) and covers at least theexposed side surface of the active layer 23 of the light emitting part20.

The underlying layer 11 has the same structure as that in the firstembodiment but has a different configuration.

Specifically, in the third embodiment, the substrate 10 is composed ofp-GaAs, and the III-V compound semiconductor of the underlying layer 11contains at least arsenic and aluminum. More specifically, theunderlying layer 11 is composed of e.g. p-Al_(0.47)Ga_(0.53)As:Zn, andthe first compound semiconductor layer 21 is composed ofp-Al_(0.4)Ga_(0.6)As:Zn. Therefore, the energy band gap (E_(g)) of thematerial of the underlying layer 11 is larger than the energy band gap(E_(g-0)) of the material of the substrate 10. Furthermore, the energyband gap (E_(g)) of the material of the underlying layer 11 is largerthan the energy band gap (E_(g-1)) of the material of the first compoundsemiconductor layer 21. The current block layer 40 is composed of athird compound semiconductor layer 43 of the first conductivity type(p-type) and a fourth compound semiconductor layer 44 of the secondconductivity type (n-type) in contact with the third compoundsemiconductor layer 43. FIG. 6B is a schematic partial sectional view ofthe partially-enlarged third compound semiconductor layer 43 and fourthcompound semiconductor layer 44. Details will be described later aboutthe compositions of the respective compound semiconductor layersincluded in the light emitting part 20 and the compositions of therespective compound semiconductor layers included in the current blocklayer 40 in the semiconductor light emitting device of the thirdembodiment.

A method for manufacturing a semiconductor light emitting device and amethod for forming an underlying layer according to the third embodimentwill be described below.

[Step-300]

Initially, similarly to [Step-100] of the first embodiment, plural masklayers 11A extending along the <110> direction are formed on the majorsurface of the substrate 10 having the {100} plane as the major surface,and a part of the major surface of the substrate 10 is exposed betweenthe mask layers 11A. Alternatively, the plural mask layers 11A areformed on the major surface of the substrate 10, and a part of the majorsurface of the substrate 10 is exposed between the mask layers 11A.Specifically, on the {100} crystal plane, e.g. the (100) crystal plane,of the substrate 10 composed of p-GaAs as its major surface, the masklayers 11A that are formed of SiO₂ layers with a required width andextend along the [011]A direction are formed based on CVD and aphotolithography technique.

[Step-310]

Subsequently, similarly to [Step-110] of the first embodiment, theunderlying layer 11 that is composed of a III-V compound semiconductorand has the following feature is epitaxially grown on the exposed partof the major surface of the substrate 10. Specifically, the sectionalshape of the underlying layer 11 obtained when the underlying layer 11is cut along a virtual plane perpendicular to the <110> direction of thesubstrate 10 is a trapezoid. Furthermore, the oblique surfaces of theunderlying layer 11 corresponding to two oblique sides of this trapezoidare the {111}B planes, and the top surface of the underlying layer 11corresponding to the upper side of the trapezoid is the {100} plane.Subsequently to the epitaxial growth of the underlying layer 11, themask layers 11A are removed. Alternatively, the underlying layer 11composed of a III-V compound semiconductor is epitaxially grown on theexposed part of the major surface of the substrate 10, and then the masklayers 11A are removed. To the material used for the epitaxial growth ofthe underlying layer 11 having the p conductivity type, an impuritywhose substitution site is the site occupied by a group III atom and animpurity whose substitution site is the site occupied by a group V atomare added in order to cause the underlying layer 11 to have the pconductivity type.

Specifically, e.g. the same material gases of the aluminum (Al) source,the gallium (Ga) source, and the arsenic (As) source as those in thefirst embodiment are used. Furthermore, as the gas for p-type impuritydoping, e.g. trimethylzinc (TMZn), triethylzinc (TEZn),biscyclopentadienyl magnesium (Cp₂Mg), bisethylcyclopentadienylmagnesium (EtCp₂Mg), bisisopropylcyclopentadienyl magnesium (i-PrCp₂Mg),bismethylcyclopentadienyl magnesium (MeCp₂Mg), or trimethylmanganese(TMMn) is used, if the site to be substituted by the impurity is thegroup III site. In addition, as the gas for p-type impurity doping,carbon tetrachloride (CCl₄), carbon tetrabromide (CBr₄), carbontetraiodide (CI₄), or the like is used as the material gas of the carbon(C) source, if the site to be substituted by the impurity is the group Vsite. Moreover, as another carbon (C) source, a growth condition may beemployed under which methyl groups and ethyl groups contained in e.g.the material gases (organic metal gases) of the Al source, the Gasource, and the In source are aggressively captured in the crystal (usedfor autodoping), as described above for [Step-110] of the firstembodiment. Based on MOCVD, these group III gas, group V gas, andimpurity gas are introduced into a reaction chamber and subjected to apyrolytic reaction in a temperature range of 600° C. to 900° C. forhigh-temperature growth. This promotes the migration of the group IIImaterial, and thus allows the epitaxial growth of a compoundsemiconductor layer having high flatness of the {100} plane and highcrystal quality. Furthermore, due to this MOCVD, it is possible to formthe underlying layer 11 that is formed of an AlGaAs-based material layerwhose energy band gap is larger than at least that of the GaAs substrateand has a trapezoidal shape with desired top-surface width and height.

In order to further improve the flatness of the top surface of theunderlying layer 11, a growth condition that permits promotion of themigration of the group III material may be employed through adjustmentto a high flow rate of the supply gas to be introduced into the reactionchamber and adjustment to a low mole supply ratio of (group Vgas)/(group III gas). Furthermore, in order to increase theconcentration of the p-type impurity in the underlying layer 11, theabsolute amount of the dopant is increased, naturally. In addition, itis effective to use not only carbon (C) arising from methyl groups(CH₃—) and ethyl groups (C₂H₅—) but also another p-type impurity whoseimpurity substitution site does not compete with that of carbon (C).Specifically, the substitution site of carbon (C) is the group V site,and the site that does not compete with the group V site is the groupIII site. Therefore, a group III impurity material gas may be usedtogether with the carbon-containing gas. Moreover, in order to increasethe absolute amount of carbon (C) itself by autodoping, e.g. the Al molefraction of the AlGaAs-based underlying layer 11 (the gas supply amountof TMAl) may be increased to thereby increase the capturing of carbon(C), without permitting the underlying layer 11 to absorb lightgenerated by the light emitting layer. This is because of the followingreason. Specifically, e.g. TMAl forms a dimer at the time of the growthof the AlGaAs-based underlying layer 11, and thus methyl groups (CH₃—)and ethyl groups (C₂H₅—) are also easily captured in the crystaltogether with Al. Therefore, by increasing the Al mole fraction of theAlGaAs-based underlying layer 11, the capturing of carbon (C) can beincreased, and hence the autodoping amount can be increased. Inparticular, in order to further increase the autodoping amount of carbon(C) in the underlying layer 11, it is desirable to use tertiary butylarsine (TBAs) as the material gas of the arsenic (As) source. Iftertiary butyl arsine (TBAs) is used, in addition to the related-arttechnique of using only carbon (C) arising from methyl groups (CH₃—) andethyl groups (C₂H₅—) contained in the group III material (organicmetal), carbon (C) arising from tertiary butyl groups ((CH₃)₃C—)contained in the group V material (organic metal) is also used. Thisincreases the absolute amount of carbon (C), and the amount of carbon(C) substituted for the group V site in the crystal by autodoping isincreased, which can increase the hole concentration.

In this manner, the underlying layer 11 extending along the [011]Adirection can be obtained. The width direction of the underlying layer11 is parallel to the [0-11]B direction. Thereafter, the mask layers 11Acomposed of SiO₂ are removed based on wet etching. The underlying layer11 has the oblique surfaces (side surfaces) formed of the (11-1)B planeand the (1-11)B plane, and the top surface of the underlying layer 11 isthe (100) plane. The obtained underlying layer 11 contains, asimpurities, zinc (impurity whose substitution site is the site occupiedby a group III atom) and carbon (impurity whose substitution site is thesite occupied by a group V atom) for causing the underlying layer 11 tobe the p-type.

[Step-320]

Thereafter, steps similar to [Step-120] to [Step-150] of the firstembodiment are carried out, so that the semiconductor light emittingdevice of the third embodiment can be achieved.

As an alternative, the following configuration may be employed.Specifically, the substrate 10 is composed of n-GaAs. Furthermore,subsequently to the step similar to [Step-100], on the exposed part ofthe major surface of the substrate 10, a base layer of the nconductivity type (specifically, an n-Al_(x1)Ga_((1-x1))As layer[0≦x1≦1], and in particular, an n⁺⁺-Al_(x1)Ga_((1-x1))As layer [0<x1≦1]or a superlattice layer formed of an n⁺⁺-GaAs layer may be used at theuppermost part (top surface part) of the n-type base layer closest tothe underlying layer) is epitaxially grown. Subsequently, in the stepsimilar to [Step-110], the underlying layer 11 composed of theabove-described III-V compound semiconductor is epitaxially grown on thebase layer. In this configuration, a tunnel junction is formed by thebase layer and the underlying layer 11. In the case of a mere npjunction (the np junction between the base layer and the underlyinglayer), current flowing in the reverse direction attributed to thetunnel effect will not occur basically. However, the thickness of thedepletion layer can be further adjusted depending on the impurityconcentration for example. Therefore, in order to cause the tunneleffect, the impurity concentrations of the respective layers in theregion around the junction interface may be set as high as possiblewithout significantly deteriorating the crystal quality. This decreasesthe width of the depletion layer formed across the junction interface.Thus, the tunnel effect is readily caused when a reverse bias isapplied. Furthermore, the tunnel effect will occur more readily when theband gap of the semiconductor is smaller. Therefore, the materials maybe so selected that, at least in the interface junction structure part,one of the outermost layer (top surface layer) of the base layer and thelowermost layer of the underlying layer closest to the base layer has asmall energy band gap while the other of the layers has a large energyband gap. In addition, by using this compound semiconductor layer as asuperlattice layer partially (using a very thin layer), the percentageof the material having the small energy band gap can be suppressed tothe minimum, which makes it possible to suppress the absorption amountof light generated by the light emitting layer to the minimum necessary.In this manner, a condition with attention on the impurityconcentrations, energy band gaps, and thicknesses of the compoundsemiconductor layers that form the interface between the base layer andthe underlying layer and are in the vicinity of the interface may beemployed.

At least around the interface between the base layer and the underlyinglayer and the vicinity of the interface, an impurity whose substitutionsite is the site occupied by a group III atom and an impurity whosesubstitution site is the site occupied by a group V atom are added tothe material used for the epitaxial growth of the base layer having then conductivity type in order to cause the base layer to have the nconductivity type. Specifically, as the material used for the epitaxialgrowth of the base layer, for example, trimethylaluminum (TMAl) ortriethylaluminum (TEAl) is used as the material gas of the aluminum (Al)source, and trimethylgallium (TMGa) or triethylgallium (TEGa) is used asthe material gas of the gallium (Ga) source. In addition, tertiary butylarsine (TBAs) or arsine (AsH₃) is used as the material gas of thearsenic (As) source. Furthermore, as the gas for n-type impurity doping,e.g. disilane (Si₂H₆), monosilane (SiH₄), or trimethyltin (TMSn) isused, if the site to be substituted by the impurity is the group IIIsite. In addition, as the gas for n-type impurity doping, hydrogensulfide (H₂S), hydrogen selenide (H₂Se), or hydrogen telluride (H₂Te) isused, if the site to be substituted by the impurity is the group V site.In particular, for the tunnel junction part formed by the n-type baselayer and the p-type underlying layer and the vicinity thereof, the baselayer formed of an n⁺⁺-type layer (heavily-doped layer) and the p⁺⁺-typeunderlying layer should be used. Therefore, it is important that, as thegases for the impurity doping for the n⁺⁺-type base layer, at least twokinds of gases by which the group III site and the group V site are tobe substituted by impurities be used for the same layer.

Fourth Embodiment

The fourth embodiment is a modification of the third embodiment. In thefourth embodiment, the III-V compound semiconductor of the underlyinglayer 11 contains at least phosphorus. More specifically, the underlyinglayer 11 is composed of e.g. n-{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P:Se[0≦x4≦1, x5=0.5, specifically, e.g. x4=0, 0.1, 0.2, 0.3, or 1], whichreadily achieves lattice matching with the substrate composed of GaAs,and the first compound semiconductor layer 21 is composed ofp-Al_(0.4)Ga_(0.6)As:Zn. Therefore, the energy band gap (E_(g)) of thematerial of the underlying layer 11 is larger than the energy band gap(E_(g-0)) of the material of the substrate 10. Furthermore, the energyband gap (E_(g)) of the material of the underlying layer 11 is largerthan the energy band gap (E_(g-1)) of the material of the first compoundsemiconductor layer 21.

In a method for manufacturing a semiconductor light emitting device anda method for forming an underlying layer according to the fourthembodiment, in a step similar to [Step-310] of the third embodiment, thematerial gases described for the second embodiment are used as thematerial gases of the aluminum (Al) source, the gallium (Ga) source, theindium (In) source, and the phosphorus (P) source. Furthermore, as thegas for p-type impurity doping, the material gas described for the thirdembodiment is used, if the site to be substituted by the impurity is thegroup III site. In addition, as the gas for p-type impurity doping, thematerial gas of the carbon (C) source described for the third embodimentis used, if the site to be substituted by the impurity is the group Vsite. Moreover, as another carbon (C) source, a growth condition may beemployed under which methyl groups and ethyl groups contained in e.g.the material gases (organic metal gases) of the Al source, the Gasource, and the In source are aggressively captured in the crystal (usedfor autodoping), as described above for [Step-110] of the firstembodiment. Based on MOCVD, these group III gas, group V gas, andimpurity gas are introduced into a reaction chamber and subjected to apyrolytic reaction in a temperature range of 600° C. to 900° C. forhigh-temperature growth. This promotes the migration of the group IIImaterial, and thus allows the epitaxial growth of a compoundsemiconductor layer having high flatness of the {100} plane and highcrystal quality. Furthermore, due to this MOCVD, it is possible to formthe underlying layer 11 that is formed of an AlGaAs-based material layerwhose energy band gap is larger than at least that of the GaAs substrateand has a trapezoidal shape with desired top-surface width and height.

In order to further improve the flatness of the top surface of theunderlying layer 11, a growth condition that permits promotion of themigration of the group III material may be employed through adjustmentto a high flow rate of the supply gas to be introduced into the reactionchamber and adjustment to a low mole supply ratio of (group Vgas)/(group III gas). Furthermore, in order to increase theconcentration of the p-type impurity in the underlying layer 11, theabsolute amount of the dopant is increased, naturally. In addition, itis effective to use not only carbon (C) arising from methyl groups(CH₃—) and ethyl groups (C₂H₅—) but also another p-type impurity whoseimpurity substitution site does not compete with that of carbon (C).Specifically, the substitution site of carbon (C) is the group V site,and the site that does not compete with the group V site is the groupIII site. Therefore, a group III impurity material gas may be usedtogether with the carbon-containing gas. Moreover, in order to increasethe absolute amount of carbon (C) itself by autodoping, e.g. the Al molefraction of the AlGaInP-based or AlGaAs-based underlying layer 11 (thegas supply amount of TMAl) may be increased to thereby increase thecapturing of carbon (C), without permitting the underlying layer 11 toabsorb light generated by the light emitting layer. This is because ofthe following reason. Specifically, e.g. TMAl forms a dimer at the timeof the growth of the AlGaInP-based or AlGaAs-based underlying layer 11,and thus methyl groups (CH₃—) and ethyl groups (C₂H₅—) are also easilycaptured in the crystal together with Al. Therefore, by increasing theAl mole fraction of the AlGaInP-based or AlGaAs-based underlying layer11, the capturing of carbon (C) can be increased, and hence theautodoping amount can be increased. In particular, in order to furtherincrease the autodoping amount of carbon (C) in the underlying layer 11,it is desirable to use tertiary butyl phosphine (TBP) as the materialgas of the phosphorus (P) source. If tertiary butyl phosphine (TBP) isused, in addition to the related-art technique of using only carbon (C)arising from methyl groups (CH₃—) and ethyl groups (C₂H₅—) contained inthe group III material (organic metal), carbon (C) arising from tertiarybutyl groups ((CH₃)₃C—) contained in the group V material (organicmetal) is also used. This increases the absolute amount of carbon (C),and the amount of carbon (C) substituted for the group V site in thecrystal by autodoping is increased, which can increase the holeconcentration.

In particular, the material characteristic of the AlGaInP-based materialis such that the {111}B plane (side surface) of the underlying layer 11formed by using the AlGaInP-based material (containing no As) growsgreatly readily compared with the {111}B plane (side surface) of theunderlying layer 11 formed by using the AlGaAs-based material(containing As) (the range of the condition under which the {111}B planegrows is greatly wider in the case of the AlGaInP-based material).Therefore, selection of the material gas of the phosphorus (P) source isimportant for widening of the control range of the {111}B plane (sidesurface) growth of the AlGaInP-based material (e.g. for realization ofthe turning of the {111}B plane (side surface) to a non-growth surface).As this selection, it is desirable to use tertiary butyl phosphine(TBP), which is excellent in the low-temperature decompositionefficiency. By using such a group V material gas with highlow-temperature decomposition efficiency, even with a smaller molesupply amount of the material gas compared with that of phosphine (PH₃),whose decomposition efficiency is low, the same effective mole supplyratio of group V/group III can be realized at the time of pyrolysis.Therefore, when the gas mole supply amount is the same, tertiary butylphosphine (TBP) is advantageous over phosphine (PH₃) in terms of thefollowing feature. Specifically, using tertiary butyl phosphine (TBP)allows, only through wide-range flow rate adjustment by a mass flowcontroller (MFC), changing in the condition range in which the effectivemole supply ratio of group V/group III is high for a wide temperaturerange from a temperature for low-temperature growth to a temperature forhigh-temperature growth. This makes it possible to variously treat thecontrol of the crystal planes of the underlying layer 11 (e.g. theflatness of the {100} plane and the degree of the growth of the {111}Bplane). Because the present case relates to an example of the material“containing no As,” the description thereof is made with use of tertiarybutyl phosphine (TBP) as the material gas having excellentcharacteristics. However, it is obvious that, in the case of an exampleof the material “containing As,” the description can be made with use oftertiary butyl arsine (TBAs) as the material gas having excellentcharacteristics similarly.

As an alternative, the following configuration may be employed.Specifically, the substrate 10 is composed of n-GaAs. Furthermore,subsequently to the step similar to [Step-100], on the exposed part ofthe major surface of the substrate 10, a base layer of the nconductivity type (specifically, ann-{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P layer [0≦x4≦1, x5=0.5], and inparticular, an n⁺⁺-{Al_(x4)Ga_((1-x4))}_(x5)In_((1-x5))P layer [0≦x4≦1,x5=0.5] or a superlattice layer formed of an n⁺⁺-GaAs layer may be usedat the uppermost part (top surface part) of the n-type base layerclosest to the underlying layer) is epitaxially grown. Subsequently, inthe step similar to [Step-110], the underlying layer 11 composed of theabove-described III-V compound semiconductor is epitaxially grown on thebase layer. In this configuration, a tunnel junction is formed by thebase layer and the underlying layer 11. In the case of a mere npjunction (the np junction between the base layer and the underlyinglayer), current flowing in the reverse direction attributed to thetunnel effect will not occur basically. However, the thickness of thedepletion layer can be further adjusted depending on the impurityconcentration for example. Therefore, in order to cause the tunneleffect, the impurity concentrations of the respective layers in theregion around the junction interface may be set as high as possiblewithout significantly deteriorating the crystal quality. This decreasesthe width of the depletion layer formed across the junction interface.Thus, the tunnel effect is readily caused when a reverse bias isapplied. Furthermore, the tunnel effect will occur more readily when theband gap of the semiconductor is smaller. Therefore, the materials maybe so selected that, at least in the interface junction structure part,one of the outermost layer (top surface layer) of the base layer and thelowermost layer of the underlying layer closest to the base layer has asmall energy band gap while the other of the layers has a large energyband gap. In addition, by using this compound semiconductor layer as asuperlattice layer partially (using a very thin layer), the percentageof the material having the small energy band gap can be suppressed tothe minimum, which makes it possible to suppress the absorption amountof light generated by the light emitting layer to the minimum necessary.In this manner, a condition with attention on the impurityconcentrations, energy band gaps, and thicknesses of the compoundsemiconductor layers that form the interface between the base layer andthe underlying layer and are in the vicinity of the interface may beemployed.

At least around the interface between the base layer and the underlyinglayer and the vicinity of the interface, an impurity whose substitutionsite is the site occupied by a group III atom and an impurity whosesubstitution site is the site occupied by a group V atom are added tothe material used for the epitaxial growth of the base layer having then conductivity type in order to cause the base layer to have the nconductivity type. Specifically, as the material used for the epitaxialgrowth of the base layer, for example, trimethylaluminum (TMAl) ortriethylaluminum (TEAl) is used as the material gas of the aluminum (Al)source, and trimethylgallium (TMGa) or triethylgallium (TEGa) is used asthe material gas of the gallium (Ga) source. Furthermore,trimethylindium (TMIn) or triethylindium (TEIn) is used as the materialgas of the indium (In) source, and tertiary butyl phosphine (TBP) orphosphine (PH₃) is used as the material gas of the phosphorus (P)source. In addition, tertiary butyl arsine (TBAs) or arsine (AsH₃) isused as the material gas of the arsenic (As) source. Furthermore, as thegas for n-type impurity doping, e.g. disilane (Si₂H₆), monosilane(SiH₄), or trimethyltin (TMSn) is used, if the site to be substituted bythe impurity is the group III site. In addition, as the gas for n-typeimpurity doping, hydrogen sulfide (H₂₅), hydrogen selenide (H₂Se), orhydrogen telluride (H₂Te) is used, if the site to be substituted by theimpurity is the group V site. In particular, for the tunnel junctionpart formed by the n-type base layer and the p-type underlying layer andthe vicinity thereof, the base layer formed of an n⁺⁺-type layer(heavily-doped layer) and the p⁺⁺-type underlying layer should be used.Therefore, it is important that, as the gases for the impurity dopingfor the n⁺⁺-type base layer, at least two kinds of gases by which thegroup III site and the group V site are to be substituted by impuritiesbe used for the same layer.

Except for the above-described features, the semiconductor lightemitting device, the method for manufacturing the same, and the methodfor forming an underlying layer according to the fourth embodiment canbe considered the same as those according to the third embodiment.Therefore, the detailed description thereof is omitted.

When the features of the underlying layer 11 that can be realized aresummarized by combining the concepts of the underlying layers describedfor the first to fourth embodiments, the following items (1) to (4) canbe obtained:

(1) the underlying layer 11 whose light absorption is suppressed;

(2) the underlying layer 11 that is excellent in the uniformity of thewidth and the aspect ratio in the substrate;

(3) the underlying layer 11 that is allowed to have a higherconcentration of a p-type impurity or an n-type impurity; and

(4) the underlying layer 11 that allows formation of p⁺/n⁺ junction(tunnel junction).

In particular, regarding the tunnel junction of item (4), as describedabove, as specific examples of the structure formed around the junctioninterface between the base layer and the underlying layer and thevicinity thereof, a heavily-doped (Al)GaAs-based layer, a heavily-doped(Al)GalnP-based layer, and a heavily-doped GaAs layer are cited as ann⁺⁺-type compound semiconductor layer and a p⁺⁺-type compoundsemiconductor layer, in terms of selective growth that readily allowslattice matching with the GaAs substrate. However, the selection of thematerials of the base layer and the underlying layer is not limitedthereto as long as the lattice matching with the substrate is ensured.Also when a substrate composed of a material other than GaAs is used,the base layer and the underlying layer that readily achieve the tunneleffect can be obtained by combining group III and V materials throughselection of the group III material from B, Al, Ga, and In and selectionof the group V material from N, P, As, Sb, and Bi. In particular, when ahigh-quality light emitting device that is favorable in terms of all ofthe tunnel effect, the light absorption, and the lattice matching isintended, partially employing a superlattice layer for the tunneljunction interface allows adjustment of the critical thickness whilereducing the light absorption amount as much as possible.

By the Way, the current block layer 40 obtained through crystal growthabove the exposed surface of the substrate 10 is composed of a {311}Bcrystal plane region that extends from the side surface of the lightemitting part 20, a {100} crystal plane region that extends along themajor surface of the substrate 10, and a {h11}B crystal plane region (his an integer equal to or larger than four, and it will be oftenreferred to as a high-order crystal plane region, for convenience) thatis located between the {311}B crystal plane region and the {100} crystalplane region (see FIGS. 1B and 6B).

In particular, the following problem often arises in the {h11}B crystalplane region and the vicinity of this region. Specifically, the currentblock layer 40 is annihilated or thinned due to impurity mutualdiffusion between the n-type compound semiconductor layer and the p-typecompound semiconductor layer of the current block layer 40.Consequently, the effect of the current block layer 40 becomes unstableand thus leakage current is increased. In order to solve such a problem,in a technique disclosed in the above-mentioned Japanese Patent No.2990837, a p-type substrate is used as the substrate and the currentblock layer 40 is formed of a p-type compound semiconductor layer. Thereis a tendency that the {311}B crystal plane region is readily turned toan n-type region and the high-order crystal plane region is readilyturned to a p-type region. Therefore, the thickness of the {311}Bcrystal plane region is eventually decreased from the original p-typeepitaxial growth thickness, so that this region becomes a thin filmpart. On the other hand, the thickness of the high-order crystal planeregion is eventually increased due to the turning to a p-type region, sothat this region becomes a thick film part. As a result, the thicknessof the high-order crystal plane region of the current block layer 40becomes large, and thus leakage current of this part can be surelyavoided. As above, the technique disclosed in Japanese Patent No.2990837 is very effective to solve the above-described problem. However,using an n-type substrate is strongly demanded. Furthermore, also in thecase of using a p-type substrate, it is desirable to further reduceleakage current of the current block layer. The above-described problemwill be referred to as the second problem for the following description.

In order to meet the second need, the semiconductor light emittingdevice according to the embodiment of the present invention may have thefollowing configuration. Specifically,

-   -   the current block layer is composed of a third compound        semiconductor layer of the first conductivity type and a fourth        compound semiconductor layer of the second conductivity type in        contact with the third compound semiconductor layer,

the impurity for causing the first compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the first compound semiconductor layer does not compete withthe substitution site of the impurity in the second compoundsemiconductor layer for causing the second compound semiconductor layerto have the second conductivity type, and

the impurity for causing the third compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the third compound semiconductor layer competes with thesubstitution site of the impurity in the fourth compound semiconductorlayer for causing the fourth compound semiconductor layer to have thesecond conductivity type. For convenience, this configuration will bereferred to as “the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention.” In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed.

The semiconductor light emitting device according to the ((I)-1)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-A)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group V atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-B)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group III atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-a)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer, the substitution site of the impurity in the 1A-thcompound semiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is a site occupied by a group V atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-b)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group V atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-C)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-D)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group V atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-c)-thconfiguration of the present invention.”

In addition, the semiconductor light emitting device according to the((I)-1)-th configuration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom, and

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-1-d)-thconfiguration of the present invention.”

The above-described semiconductor light emitting devices according tothe ((I)-1-A)-th configuration, ((I)-1-a)-th configuration, ((I)-1-B)-thconfiguration, ((I)-1-b)-th configuration, ((I)-1-C)-th configuration,((I)-1-c)-th configuration, ((I)-1-D)-th configuration, and ((I)-1-d)-thconfiguration of the present invention, may have the followingconfiguration. Specifically,

the current block layer further includes a fifth compound semiconductorlayer of the second conductivity type,

the third compound semiconductor layer is sandwiched by the fourthcompound semiconductor layer and the fifth compound semiconductor layer,and

the impurity for causing the third compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the third compound semiconductor layer competes with thesubstitution site of the impurity in the fifth compound semiconductorlayer for causing the fifth compound semiconductor layer to have thesecond conductivity type. In this configuration, the multilayerstructure composed of the fourth compound semiconductor layer, the thirdcompound semiconductor layer, and the fifth compound semiconductor layerstacked in that order from the lower side may be employed.Alternatively, the multilayer structure composed of the fifth compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer stacked in that order from the lowerside may be employed. In addition, the following configuration is alsoavailable. Specifically,

the current block layer further includes a sixth compound semiconductorlayer of the first conductivity type,

the fourth compound semiconductor layer is sandwiched by the thirdcompound semiconductor layer and the sixth compound semiconductor layer,and

the impurity for causing the fourth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fourth compound semiconductor layer competes with thesubstitution site of the impurity in the sixth compound semiconductorlayer for causing the sixth compound semiconductor layer to have thefirst conductivity type. In this configuration, the multilayer structurecomposed of the third compound semiconductor layer, the fourth compoundsemiconductor layer, and the sixth compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the sixth compound semiconductor layer,the fourth compound semiconductor layer, and the third compoundsemiconductor layer stacked in that order from the lower side may beemployed.

In order to meet the above-mentioned second need, the semiconductorlight emitting device according to the embodiment of the presentinvention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the impurity for causing the first compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity, and

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-2-A)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-2-A)-th configuration of thepresent invention, the number of combinations of (the impurity in thefirst compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 3×2=6.

The first compound semiconductor layer containing a group VI impurity isthe part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed.

In addition, in order to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity, and

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-2-B)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-2-B)-th configuration of thepresent invention, the number of combinations of (the impurity in the1A-th compound semiconductor layer, the impurity in the 1B-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the 2A-th compound semiconductor layer, theimpurity in the third compound semiconductor layer, and the impurity inthe fourth compound semiconductor layer) is 2×3×4×1×2×4=192.

In addition, in order to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the impurity for causing the first compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity, and

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C). Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-2-C)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-2-C)-th configuration of thepresent invention, the number of combinations of (the impurity in thefirst compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 4×1=4.

The first compound semiconductor layer containing a group II impurity isthe part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed.

In addition, in ordet to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C), and

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-2-D)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-2-D)-th configuration of thepresent invention, the number of combinations of (the impurity in the1A-th compound semiconductor layer, the impurity in the 1B-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the 2A-th compound semiconductor layer, theimpurity in the third compound semiconductor layer, and the impurity inthe fourth compound semiconductor layer) is 1×4×3×2×1×3=72.

In addition, in ordet to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the impurity for causing the second compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity, and

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C). Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-3-a)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-3-a)-th configuration of thepresent invention, the number of combinations of (the impurity in thesecond compound semiconductor layer, and the impurity in the fourthcompound semiconductor layer) is 4×1=4.

The second compound semiconductor layer containing a group II impurityis the part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed.

In addition, in order to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity, and

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C). Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-3-b)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-3-b)-th configuration of thepresent invention, the number of combinations of (the impurity in the1A-th compound semiconductor layer, the impurity in the 1B-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the 2A-th compound semiconductor layer, theimpurity in the third compound semiconductor layer, and the impurity inthe fourth compound semiconductor layer) is 2×3×4×1×3×1=72.

In addition, in order to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the impurity for causing the second compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity, and

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-3-c)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-3-c)-th configuration of thepresent invention, the number of combinations of (the impurity in thesecond compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 2×3=6.

The second compound semiconductor layer containing a group VI impurityis the part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed.

In addition, in ordet to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity, and

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-3-d)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-3-d)-th configuration of thepresent invention, the number of combinations of (the impurity in the1A-th compound semiconductor layer, the impurity in the 1B-th compoundsemiconductor layer, the impurity in the 2A-th compound semiconductorlayer, the impurity in the 2B-th compound semiconductor layer, theimpurity in the third compound semiconductor layer, the impurity in thefourth compound semiconductor layer, the impurity in the first buryinglayer, and the impurity in the second burying layer) is 1×4×3×2×4×2=192.

In addition, in order to meet the above-mentioned second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have a configuration in which

the current block layer is composed of a third compound semiconductorlayer of the first conductivity type and a fourth compound semiconductorlayer of the second conductivity type in contact with the third compoundsemiconductor layer, and

the impurity for causing the first compound semiconductor layer to havethe first conductivity type is different from the impurity for causingthe third compound semiconductor layer to have the first conductivitytype. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-4-A)-thconfiguration of the present invention.”

The first compound semiconductor layer containing the impurity differentfrom the impurity for causing the third compound semiconductor layer tohave the first conductivity type is the part that is in contact with atleast the active layer, specifically. The active layer with which thefirst compound semiconductor layer is in contact encompasses well layersand confinement layers. This applies also to the following description.The provision of the confinement layer allows light confinement and/orcarrier confinement. In this configuration, the multilayer structurecomposed of the fourth compound semiconductor layer and the thirdcompound semiconductor layer stacked in that order from the lower sidemay be employed. Alternatively, the multilayer structure composed of thethird compound semiconductor layer and the fourth compound semiconductorlayer stacked in that order from the lower side may be employed.

In addition, in order to meet the above-described second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have a configuration in which

the current block layer is composed of a third compound semiconductorlayer of the first conductivity type and a fourth compound semiconductorlayer of the second conductivity type in contact with the third compoundsemiconductor layer, and

the impurity for causing the second compound semiconductor layer to havethe second conductivity type is different from the impurity for causingthe fourth compound semiconductor layer to have the second conductivitytype. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-4-a)-thconfiguration of the present invention.”

The second compound semiconductor layer containing the impuritydifferent from the impurity for causing the fourth compoundsemiconductor layer to have the second conductivity type is the partthat is in contact with at least the active layer (including well layersand confinement layers), specifically. In this configuration, themultilayer structure composed of the fourth compound semiconductor layerand the third compound semiconductor layer stacked in that order fromthe lower side may be employed. Alternatively, the multilayer structurecomposed of the third compound semiconductor layer and the fourthcompound semiconductor layer stacked in that order from the lower sidemay be employed.

In addition, in order to meet the above-described second need, thesemiconductor light emitting device according to the embodiment of thepresent invention may have the following configuration. Specifically,

the current block layer is formed of a multilayer structure arising fromsequential stacking of at least the fourth compound semiconductor layerof the second conductivity type and the third compound semiconductorlayer of the first conductivity type,

the impurity for causing the fourth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fourth compound semiconductor layer competes with thesubstitution site of the impurity in the third compound semiconductorlayer for causing the third compound semiconductor layer to have thefirst conductivity type, and competes with the substitution site of theimpurity in the first compound semiconductor layer for causing the firstcompound semiconductor layer to have the first conductivity type,

the impurity for causing the second compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the second compound semiconductor layer competes with thesubstitution site of the impurity in the third compound semiconductorlayer for causing the third compound semiconductor layer to have thefirst conductivity type, and

if a bypass channel that passes through the first compound semiconductorlayer, the current block layer, and the second compound semiconductorlayer is assumed, at least three pn junction interfaces formed of theinterfaces between the compound semiconductor layers exist in the bypasschannel. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5)-thconfiguration of the present invention.”

It is possible for the semiconductor light emitting device according tothe ((I)-5)-th configuration of the present invention to have a form inwhich the fourth compound semiconductor layer is in contact with theside surface of the first compound semiconductor layer and the thirdcompound semiconductor layer is in contact with the side surface of thesecond compound semiconductor layer. In this case, the bypass channel iscomposed of the first compound semiconductor layer, the fourth compoundsemiconductor layer, the third compound semiconductor layer, and thesecond compound semiconductor layer. The pn junction interfaces areformed of the following three interfaces: the interface between the sidesurface of the first compound semiconductor layer and the fourthcompound semiconductor layer; the interface between the fourth compoundsemiconductor layer and the third compound semiconductor layer; and theinterface between the third compound semiconductor layer and the sidesurface of the second compound semiconductor layer.

The semiconductor light emitting device according to the ((I)-5)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer, and

the impurity for causing the 1B-th compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the 1B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 1A-th compoundsemiconductor layer for causing the 1A-th compound semiconductor layerto have the first conductivity type, and does not compete with thesubstitution site of the impurity in the second compound semiconductorlayer for causing the second compound semiconductor layer to have thesecond conductivity type. In this case, the impurity for causing the1A-th compound semiconductor layer to have the first conductivity typeis such that the substitution site of the impurity in the 1A-th compoundsemiconductor layer competes with the substitution site of the impurityin the fourth compound semiconductor layer for causing the fourthcompound semiconductor layer to have the second conductivity type.

In the case of the configuration in which the 1B-th compoundsemiconductor layer is used, the relationship between the 1B-th compoundsemiconductor layer and the fourth compound semiconductor layer incontact with the side surface of the 1B-th compound semiconductor layeris such that their impurity substitution sites do not compete with eachother in some cases. In such a case, initially impurity diffusionbetween the 1B-th compound semiconductor layer and the fourth compoundsemiconductor layer will occur across this side surface part, and thenthe impurity diffusion will reach the third compound semiconductor layerincluded in the current block layer, so that a current leakage path ispossibly formed.

Therefore, for this case, the following configuration may be employed.Specifically, a sixth compound semiconductor layer of the firstconductivity type is provided under the fourth compound semiconductorlayer,

the impurity for causing the sixth compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the sixth compound semiconductor layer competes with thesubstitution site of the impurity in the first compound semiconductorlayer (or the 1A-th compound semiconductor layer) for causing the firstcompound semiconductor layer (or the 1A-th compound semiconductor layer)to have the first conductivity type, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer. Employing such aconfiguration eliminates the contact between the 1B-th compoundsemiconductor layer and the fourth compound semiconductor layer, whoseimpurity substitution sites do not compete with each other, and thus canprevent the impurity diffusion. In this case, the bypass channel iscomposed of the first compound semiconductor layer (the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer), thesixth compound semiconductor layer, the fourth compound semiconductorlayer, the third compound semiconductor layer, and the second compoundsemiconductor layer. The pn junction interfaces are formed of thefollowing three interfaces: the interface between the sixth compoundsemiconductor layer and the fourth compound semiconductor layer; theinterface between the fourth compound semiconductor layer and the thirdcompound semiconductor layer; and the interface between the thirdcompound semiconductor layer and the side surface of the second compoundsemiconductor layer.

In addition, in such a case, it is desirable to provide an impuritydiffusion barrier layer in the current block layer in order to preventthe occurrence of current leakage attributed to impurity diffusion fromthe 1B-th compound semiconductor layer into the current block layer.Specifically, a seventh compound semiconductor layer of the secondconductivity type whose impurity substitution site is different fromthat of the fourth compound semiconductor layer of the secondconductivity type is provided as the “impurity diffusion barrier layer.”More specifically, in the fourth compound semiconductor layer that isincluded in the current block layer and has the second conductivitytype, at least one impurity diffusion barrier layer having the secondconductivity type (e.g. the seventh compound semiconductor layer) isprovided. Furthermore, impurities are so selected that the substitutionsite of the impurity in the fourth compound semiconductor layer isdifferent from that of the impurity in the impurity diffusion barrierlayer (e.g. the seventh compound semiconductor layer if the number ofimpurity diffusion barrier layers is one). Employing such aconfiguration allows further-ensured prevention of the phenomenon that acurrent leakage path from the bypass channel is formed due to impuritydiffusion into the current block layer.

Furthermore, the semiconductor light emitting device according to the((I)-5)-th configuration of the present invention may have the followingconfiguration. Specifically,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer, and

the impurity for causing the 2B-th compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the 2B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 2A-th compoundsemiconductor layer for causing the 2A-th compound semiconductor layerto have the second conductivity type, and does not compete with thesubstitution site of the impurity in the first compound semiconductorlayer for causing the first compound semiconductor layer to have thefirst conductivity type. In this case, the impurity for causing the2A-th compound semiconductor layer to have the second conductivity typeis such that the substitution site of the impurity in the 2A-th compoundsemiconductor layer competes with the substitution site of the impurityin the third compound semiconductor layer for causing the third compoundsemiconductor layer to have the first conductivity type.

In the case of the configuration in which the 2B-th compoundsemiconductor layer is used, the relationship between the 2B-th compoundsemiconductor layer and the third compound semiconductor layer incontact with the side surface of the 2B-th compound semiconductor layeris such that their impurity substitution sites do not compete with eachother in some cases. In such a case, initially impurity diffusionbetween the 2B-th compound semiconductor layer and the third compoundsemiconductor layer will occur across this side surface part, and thenthe impurity diffusion will reach the fourth compound semiconductorlayer included in the current block layer, so that a current leakagepath is possibly formed.

Therefore, for this case, the following configuration may be employed.Specifically, a fifth compound semiconductor layer of the secondconductivity type is provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fifth compound semiconductor layer competes with thesubstitution site of the impurity in the second compound semiconductorlayer (or the 2A-th compound semiconductor layer) for causing the secondcompound semiconductor layer (or the 2A-th compound semiconductor layer)to have the second conductivity type, and

the fourth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer and the fifth compoundsemiconductor layer is in contact with the side surface of the secondcompound semiconductor layer (at least a part of the side surface of the2A-th compound semiconductor layer and all of the side surface of the2B-th compound semiconductor layer). Employing such a configurationeliminates the contact between the 2B-th compound semiconductor layerand the third compound semiconductor layer, whose impurity substitutionsites do not compete with each other, and thus can prevent the impuritydiffusion. In this case, the bypass channel is composed of the firstcompound semiconductor layer, the fourth compound semiconductor layer,the third compound semiconductor layer, the fifth compound semiconductorlayer, and the second compound semiconductor layer (the 2B-th compoundsemiconductor layer and the 2A-th compound semiconductor layer). The pnjunction interfaces are formed of the following three interfaces: theinterface between the side surface of the first compound semiconductorlayer and the fourth compound semiconductor layer; the interface betweenthe fourth compound semiconductor layer and the third compoundsemiconductor layer; and the interface between the third compoundsemiconductor layer and the fifth compound semiconductor layer.

In addition, in such a case, it is desirable to provide an impuritydiffusion barrier layer in the current block layer in order to preventthe occurrence of current leakage attributed to impurity diffusion fromthe 2B-th compound semiconductor layer into the current block layer.Specifically, an eighth compound semiconductor layer of the firstconductivity type whose impurity substitution site is different fromthat of the third compound semiconductor layer of the first conductivitytype is provided as the “impurity diffusion barrier layer.” Morespecifically, in the third compound semiconductor layer that is includedin the current block layer and has the first conductivity type, at leastone impurity diffusion barrier layer having the first conductivity type(e.g. the eighth compound semiconductor layer) is provided. Furthermore,impurities are so selected that the substitution site of the impurity inthe third compound semiconductor layer is different from that of theimpurity in the impurity diffusion barrier layer (e.g. the eighthcompound semiconductor layer if the number of impurity diffusion barrierlayers is one). Employing such a configuration allows further-ensuredprevention of the phenomenon that a current leakage path from the bypasschannel is formed due to impurity diffusion into the current blocklayer.

In the semiconductor light emitting device according to the ((I)-5)-thconfiguration of the present invention, the first compound semiconductorlayer, the second compound semiconductor layer, the fourth compoundsemiconductor layer, and the third compound semiconductor layer arecomposed of a III-V compound semiconductor. Alternatively, the 1A-thcompound semiconductor layer, the 1B-th compound semiconductor layer,the second compound semiconductor layer, the fourth compoundsemiconductor layer, and the third compound semiconductor layer arecomposed of a III-V compound semiconductor. Alternatively, the firstcompound semiconductor layer, the 2B-th compound semiconductor layer,the 2A-th compound semiconductor layer, the fourth compoundsemiconductor layer, and the third compound semiconductor layer arecomposed of a III-V compound semiconductor.

Furthermore, the following configuration can be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. For convenience, this configuration willbe referred to as “the semiconductor light emitting device according tothe ((I)-5-A)-th configuration of the present invention.” It is possibleto employ a form in which the fourth compound semiconductor layer is incontact with the side surface of the first compound semiconductor layerand the third compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer.

The semiconductor light emitting device according to the ((I)-5-A)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity, and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((I)-5-A-1)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((I)-5-A-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 2×4×4×2=64.

In addition, the semiconductor light emitting device according to the((I)-5-A)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity, and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((I)-5-A-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((I)-5-A-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 4×2×2×4=64.

Furthermore, the following configuration can be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group V atom. For convenience, this configuration will bereferred to as “the semiconductor light emitting device according to the((I)-5-a)-th configuration of the present invention.” It is possible toemploy a form in which the fourth compound semiconductor layer is incontact with the side surface of the first compound semiconductor layerand the third compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer.

The semiconductor light emitting device according to the ((I)-5-a)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity, and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C). For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((I)-5-a-1)-th configuration of the present invention.”In the semiconductor light emitting device according to the((I)-5-a-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 3×1×1×3=9.

In addition, the semiconductor light emitting device according to the((I)-5-a)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C), and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((I)-5-a-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((I)-5-a-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, and the impurity in the thirdcompound semiconductor layer) is 1×3×3×1=9.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the 1A-th compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 1B-th compound semiconductor layer is the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-B)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((I)-5-B)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity, and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((I)-5-B-1)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((I)-5-B-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, and the impurity in the third compoundsemiconductor layer) is 2×3×4×4×2=192.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis a group IV impurity, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((I)-5-B)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C), and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((I)-5-B-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((I)-5-B-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, and the impurity in the third compoundsemiconductor layer) is 4×1×2×2×4=64.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis a group II impurity, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the 1A-th compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group V atom. The substitution site of the impurity in the1B-th compound semiconductor layer is the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-b)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((I)-5-b)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity, and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C). For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((I)-5-b-1)-th configuration of the present invention.”In the semiconductor light emitting device according to the((I)-5-b-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, and the impurity in the third compoundsemiconductor layer) is 3×2×1×1×3=18.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis a group VI impurity, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((I)-5-b)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity, and

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((I)-5-b-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((I)-5-b-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, and the impurity in the third compoundsemiconductor layer) is 1×4×3×3×1=36.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis carbon (C), and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the 2A-thcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 2B-th compound semiconductor layer is the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-C)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((I)-5-C)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity,

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity, and

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C). Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-C-1)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-5-C-1)-th configuration of thepresent invention, the number of combinations of (the impurity in thefirst compound semiconductor layer, the impurity in the 2A-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the fourth compound semiconductor layer, and theimpurity in the third compound semiconductor layer) is 2×4×1×4×2=64.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis a group II impurity, and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((I)-5-C)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity, and

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-C-2)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-5-C-2)-th configuration of thepresent invention, the number of combinations of (the impurity in thefirst compound semiconductor layer, the impurity in the 2A-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the fourth compound semiconductor layer, and theimpurity in the third compound semiconductor layer) is 4×2×3×2×4=192.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis a group IV impurity, and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the 2A-thcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group V atom. The substitution site of the impurity in the2B-th compound semiconductor layer is the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-c)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((I)-5-c)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C), and

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-c-1)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-5-c-1)-th configuration of thepresent invention, the number of combinations of (the impurity in thefirst compound semiconductor layer, the impurity in the 2A-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the fourth compound semiconductor layer, and theimpurity in the third compound semiconductor layer) is 3×1×4×1×3=36.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis carbon (C), and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((I)-5-c)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity, and

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((I)-5-c-2)-thconfiguration of the present invention.” In the semiconductor lightemitting device according to the ((I)-5-c-2)-th configuration of thepresent invention, the number of combinations of (the impurity in thefirst compound semiconductor layer, the impurity in the 2A-th compoundsemiconductor layer, the impurity in the 2B-th compound semiconductorlayer, the impurity in the fourth compound semiconductor layer, and theimpurity in the third compound semiconductor layer) is 1×3×2×3×1=18.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis a group VI impurity, and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

In addition, in the semiconductor light emitting device according to the((I)-5)-th configuration of the present invention, a plurality ofcompound semiconductor layers may be provided between the fourthcompound semiconductor layer and the third compound semiconductor layerof the current block layer. Specifically, it is also possible to employa configuration in which at least a compound semiconductor layer of thefirst conductivity type and a compound semiconductor layer of the secondconductivity type are further sequentially stacked between the fourthcompound semiconductor layer and the third compound semiconductor layer.More specifically, if the first conductivity type is the n-type and thesecond conductivity type is the p-type, the current block layer may beformed based on a four-layer structure composed of the p-type fourthcompound semiconductor layer, an n-type compound semiconductor layer, ap-type compound semiconductor layer, and the n-type third compoundsemiconductor layer. Alternatively, the current block layer may beformed based on a six-layer structure composed of the p-type fourthcompound semiconductor layer, an n-type compound semiconductor layer, ap-type compound semiconductor layer, an n-type compound semiconductorlayer, a p-type compound semiconductor layer, and the n-type thirdcompound semiconductor layer. More alternatively, the current blocklayer may be formed based on an eight-layer structure composed of thep-type fourth compound semiconductor layer, an n-type compoundsemiconductor layer, a p-type compound semiconductor layer, an n-typecompound semiconductor layer, a p-type compound semiconductor layer, ann-type compound semiconductor layer, a p-type compound semiconductorlayer, and the n-type third compound semiconductor layer. Such amultilayer structure will be often represented as “the p-type fourthcompound semiconductor layer, (n-type compound semiconductor layer,p-type compound semiconductor layer)_(m), and the n-type third compoundsemiconductor layer (m=1, 2, 3, . . . ).” In addition, if the firstconductivity type is the p-type and the second conductivity type is then-type, the current block layer may be formed based on a multilayerstructure composed of the n-type fourth compound semiconductor layer,(p-type compound semiconductor layer, n-type compound semiconductorlayer)_(m), and the p-type third compound semiconductor layer (m=1, 2,3, . . . ). By thus forming the current block layer based on amultilayer structure, the phenomenon that a current leakage path fromthe bypass channel is formed can be prevented more surely even if arelative positional error between the light emitting part and thecurrent block layer occurred. It is desirable that the thickness of thecurrent block layer be not increased even when the current block layeris formed based on a multilayer structure. Furthermore, it is moredesirable that at least one pn interface (or np interface) between thecompound semiconductor layers included in the current block layer be incontact with the side surface of the active layer. This featuredecreases the area of the contact part with the side surface of thelight emitting part per one compound semiconductor layer included in thecurrent block layer, which results in an increase in the electricresistance. Consequently, leakage current is further suppressed and thusthe light output can be improved.

Moreover, as a more desirable form regarding the contact surface withthe side surface of the light emitting part per one compoundsemiconductor layer included in the current block layer, it is desirablethat the width of the contact surface (the length of the contact surfacealong the vertical direction of the side surface of the light emittingpart) per one compound semiconductor layer included in the current blocklayer be equal to or smaller than the total thickness of the activelayer (the length of the active layer along the vertical direction ofthe side surface of the light emitting part) sandwiched between thefirst compound semiconductor layer (or the 1B-th compound semiconductorlayer) and the second compound semiconductor layer. In addition, if theactive layer has a quantum well structure, it is desirable that thewidth of the contact surface per one compound semiconductor layerincluded in the current block layer be equal to or smaller than thewidth of one well layer of the quantum well structure (the length of thewell layer along the vertical direction of the side surface of the lightemitting part). Such a form involves the necessity that the thicknessesof the respective compound semiconductor layers included in the currentblock layer are set to very small values. Therefore, the related art hasa problem that a part of the current block layer formed of the {311}Bplane or a higher-order crystal plane is annihilated or, conversely, thethickness of this part is abnormally increased because of conductivitytype neutralization due to impurity mutual diffusion across theinterface of n-type compound semiconductor layer/p-type compoundsemiconductor layer (or p-type compound semiconductor layer/n-typecompound semiconductor layer) as described above. Consequently,according to the semiconductor light emitting device of the presentinvention, in achievement of desired conductivity types of therespective compound semiconductor layers included in the current blocklayer, the impurity combination in consideration of the competitionrelationship of the impurity substitution site is comprehensivelydetermined from the viewpoint of current leakage suppression. This makesit possible to realize a structure that allows suppression ofconductivity type neutralization due to impurity mutual diffusion,enhancement in the current block quality of the current block layeritself, and ensured suppression of leakage current from the side surfaceof the light emitting part, even when the thicknesses of the respectivecompound semiconductor layers included in the current block layer areset to very small values.

In the semiconductor light emitting device according to the ((I)-1)-thconfiguration of the present invention, the impurity for causing thethird compound semiconductor layer to have the first conductivity typeincluded in the current block layer is such that the substitution siteof the impurity in the third compound semiconductor layer competes withthe substitution site of the impurity in the fourth compoundsemiconductor layer for causing the fourth compound semiconductor layerto have the second conductivity type. Thus, impurity mutual diffusionhardly occurs between the n-type compound semiconductor layer and thep-type compound semiconductor layer of the current block layer. Thisallows avoidance of the occurrence of a problem that the effect of thecurrent block layer is unstable and thus leakage current is increaseddue to annihilation or thinning of the current block layer. Furthermore,the impurity for causing the first compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the first compound semiconductor layer does not compete withthe substitution site of the impurity in the second compoundsemiconductor layer for causing the second compound semiconductor layerto have the second conductivity type. Thus, the pn junction control,designed through intentional impurity mutual diffusion between the firstcompound semiconductor layer and the second compound semiconductorlayer, can be finely designed easily through adjustment of theconcentrations and doping positions of the impurities in the respectivelayers. This allows enhancement in the light emission characteristic.

In the semiconductor light emitting device according to the ((I)-2-A)-thconfiguration of the present invention or the ((I)-2-B)-th configurationof the present invention, the impurity for causing the first compoundsemiconductor layer or the 1B-th compound semiconductor layer to be then-type as the first conductivity type is a group VI impurity, and theimpurity for causing the third compound semiconductor layer to be then-type as the first conductivity type is a group IV impurity.Furthermore, in the semiconductor light emitting device according to the((I)-2-C)-th configuration of the present invention or the ((I)-2-D)-thconfiguration of the present invention, the impurity for causing thefirst compound semiconductor layer or the 1B-th compound semiconductorlayer to be the p-type as the second conductivity type is a group IIimpurity, and the impurity for causing the third compound semiconductorlayer to be the p-type as the second conductivity type is carbon (C).Furthermore, in the semiconductor light emitting device according to the((I)-3-a)-th configuration of the present invention or the ((I)-3-b)-thconfiguration of the present invention, the impurity for causing thesecond compound semiconductor layer or the 2B-th compound semiconductorlayer to be the p-type as the second conductivity type is a group IIimpurity, and the impurity for causing the fourth compound semiconductorlayer to be the p-type as the second conductivity type is carbon (C). Inaddition, in the semiconductor light emitting device according to the((I)-3-c)-th configuration of the present invention or the ((I)-3-d)-thconfiguration of the present invention, the impurity for causing thesecond compound semiconductor layer or the 2B-th compound semiconductorlayer to be the n-type as the second conductivity type is a group VIimpurity, and the impurity for causing the fourth compound semiconductorlayer to be the n-type as the second conductivity type is a group IVimpurity. Moreover, in the semiconductor light emitting device accordingto the ((I)-4-A)-th configuration of the present invention, the impurityfor causing the first compound semiconductor layer to have the firstconductivity type is different from the impurity for causing the thirdcompound semiconductor layer to have the first conductivity type. In thesemiconductor light emitting device according to the ((I)-4-a)-thconfiguration of the present invention, the impurity for causing thesecond compound semiconductor layer to have the second conductivity typeis different from the impurity for causing the fourth compoundsemiconductor layer to have the second conductivity type. Employingthese configurations and structures makes it possible to achieveconfiguration and structure in which impurity mutual diffusion hardlyoccurs between the n-type compound semiconductor layer and the p-typecompound semiconductor layer of the current block layer. As a result, itis possible to avoid the occurrence of a problem that the effect of thecurrent block layer is unstable and thus leakage current is increaseddue to annihilation or thinning of the current block layer. Furthermore,in the semiconductor light emitting device according to the ((I)-5)-thconfiguration of the present invention, when a bypass channel thatpasses through the first compound semiconductor layer, the current blocklayer, and the second compound semiconductor layer is assumed, at leastthree pn junction interfaces formed of the interfaces between thecompound semiconductor layers exist in the bypass channel. In addition,the impurity for causing a respective one of the compound semiconductorlayers to have a predetermined conductivity type is such that thesubstitution site of the impurity in the respective one of the compoundsemiconductor layers competes with the substitution site of the impurityin the adjacent compound semiconductor layer for causing the adjacentcompound semiconductor layer to have a predetermined conductivity type.Thus, impurity mutual diffusion hardly occurs between the n-typecompound semiconductor layer and the p-type compound semiconductor layerof the current block layer. In addition, impurity mutual diffusionhardly occurs between the n-type compound semiconductor layer and thep-type compound semiconductor layer of the current block layer and thep-type compound semiconductor layer and the n-type compoundsemiconductor layer of the light emitting part. As a result, it ispossible to avoid the occurrence of a problem that the effect of thecurrent block layer is unstable and thus leakage current is increaseddue to annihilation or thinning of the current block layer.

[Step-10]

Initially, on the {100} crystal plane, e.g. the (100) crystal plane, ofan n-GaAs substrate 10 as its major surface, a projection part 211 thathas a predetermined width and a substantially-stripe shape and extendsalong the [011]A direction is formed. The width direction of theprojection part 211 is parallel to the [0-11]B direction. In this way,the structure shown in FIG. 60A can be obtained. The projection part 211has the oblique surfaces (side surfaces) corresponding to the {111}Bplane. The planar shape of the projection part 211 is schematicallyshown in FIG. 60B. The projection part 211 has a strip shape in whichthe width of the center part is smaller than that of both the end parts.In FIG. 60B, the projection part 211 is hatched for clearly showing it.

[Step-20]

Subsequently, based on normal MOCVD, specifically, MOCVD with use of anorganic metal and a hydrogen compound as the source gas, a buffer layer12, an n-type first compound semiconductor layer 21, an active layer 23,a p-type second compound semiconductor layer 22 are epitaxially grownover the projection part 211 and recess surface 212. At this time, theoblique surfaces (side surfaces) of the compound semiconductor layersabove the projection part 211 correspond to the {111}B plane. Asdescribed above, the {111}B plane is a non-growth surface. Therefore,the multilayer structure formed by the buffer layer 12, the firstcompound semiconductor layer 21, the active layer 23, and the secondcompound semiconductor layer 22 (so-called double heterostructure) is soformed (stacked) that the double heterostructure in the region above theprojection part 211 is separated from that in the region above therecess surface 212 (i.e., a separated double heterostructure isobtained).

[Step-30]

Thereafter, continuously with the formation of the second compoundsemiconductor layer 22, a layer 30 for adjustment of the current blocklayer position (hereinafter, referred to simply as the adjustment layer30), formed of a p-type compound semiconductor layer, is formed acrossthe entire surface based on MOCVD. Furthermore, for example, a currentblock layer 40 formed of a multilayer structure composed of a p-typecompound semiconductor layer and an n-type compound semiconductor layeris formed based on MOCVD. The current block layer 40 is not grown on the{111}B plane. The current block layer 40 is so formed that the endsurfaces of the current block layer 40 cover at least the side surfacesof the active layer 23. Such configuration and structure can be achievedby properly selecting the thickness of the adjustment layer 30. In thisway, the sectional structure shown in FIG. 61 can be obtained at thecenter part of the projection part 211. On the other hand, at both theend parts of the projection part 211, the sectional structure shown inFIG. 62 can be obtained at this moment.

Here, at the center part of the projection part 211, the current blocklayer 40 is formed only on the side surfaces of the light emitting part20 (see FIG. 61). At this moment, at both the end parts of theprojection part 211, in addition to the formation of the current blocklayer 40 on the side surfaces of the light emitting part 20, the samemultilayer structure as that of the current block layer 40 is formedabove the top surface ({100} plane) of the multilayer structure of thelight emitting part 20 in such a way that the {111}B facet planes (sidesurfaces) are gradually formed and thus the width of the top surface isgradually decreased. The same multilayer structure as that of thecurrent block layer 40, formed above the top surface of the multilayerstructure of the light emitting part 20, will be referred to as adeposited layer 40″, for convenience. Between the deposited layer 40″and the top surface of the multilayer structure of the light emittingpart 20, a compound semiconductor layer 30′ having the sameconfiguration as that of the adjustment layer 30 is formed.

[Step-40]

Subsequently, a burying layer 31 and a contact layer (cap layer) 32 aresequentially formed across the entire surface based on MOCVD. At thismoment, at both the end parts of the projection part 211, the buryinglayer is formed on the top surface ({100} plane) of the deposited layer40″ in such a way that the {111}B facet planes (side surfaces) aregradually formed and thus the width of the top surface is graduallydecreased. Furthermore, if the width of the top surface is sufficientlylarge, the same multilayer structure as that of the contact layer (caplayer) 32 is formed. The burying layer on the deposited layer 40″ willbe represented as a burying layer 31″. Thereafter, a second electrode 52is formed based on vacuum evaporation on the contact layer 32 formed asthe outermost layer. Furthermore, the substrate 10 is lapped to a properthickness from the backside thereof, and then a first electrode 51 isformed based on vacuum evaporation (see FIGS. 63 and 64).

In the above-described [Step-30], at both the end parts of theprojection part 211, the deposited layer 40″having the same multilayerstructure as that of the current block layer 40 is formed above the topsurface of the multilayer structure of the light emitting part 20. Thisdeposited layer 40″ is formed of the multilayer structure composed ofthe p-type compound semiconductor layer and the n-type compoundsemiconductor layer, and therefore does not allow the passage of currenttherethrough. Thus, the current supplied from the second electrode 52reaches the contact layer (cap layer) 32 and the burying layer 31, andthen flows from the periphery of the deposited layer 40″ into the secondcompound semiconductor layer 22 via the {111}B side surfaces (contactsurfaces) in contact with the burying layer 31. That is, the currentinjection path to the active layer is limited to the {111}B sidesurfaces (contact surfaces). This results in a problem that the electricresistance is increased and thus the heat generation and the currentconsumption are increased, and hence a problem that the light emissionefficiency of the semiconductor light emitting device is decreased. Forconvenience in the following description, these problems will bereferred to as a third need.

According to an embodiment of the present invention, there is provided asemiconductor light emitting device to meet the above-described thirdneed. In this semiconductor light emitting device,

the planar shape of the active layer is a strip shape in which the widthof a center part is smaller than the width of both end parts,

the current block layer is composed of a third compound semiconductorlayer of the first conductivity type and a fourth compound semiconductorlayer of the second conductivity type in contact with the third compoundsemiconductor layer,

the burying layer has the second conductivity type and is formed of amultilayer structure arising from sequential stacking of a first buryinglayer and a second burying layer, and

in the burying layer located above the current block layer, the impurityfor causing the second burying layer to have the second conductivitytype is such that the substitution site of the impurity in the secondburying layer does not compete with the substitution site of theimpurity in the third compound semiconductor layer for causing the thirdcompound semiconductor layer to have the first conductivity type. Thesemiconductor light emitting device according to the embodiment of thepresent invention has a so-called flare-stripe structure.

In the semiconductor light emitting device according to the (II)-thconfiguration of the present invention, it is preferable that, in theburying layer located above the current block layer, the impurity forcausing the first burying layer to have the second conductivity type besuch that the substitution site of the impurity in the first buryinglayer competes with the substitution site of the impurity in the thirdcompound semiconductor layer for causing the third compoundsemiconductor layer to have the first conductivity type. Furthermore, itis preferable that, in the burying layer located above the current blocklayer, the impurity for causing the first burying layer to have thesecond conductivity type be such that the substitution site of theimpurity in the first burying layer competes with the substitution siteof the impurity in the fourth compound semiconductor layer for causingthe fourth compound semiconductor layer to have the second conductivitytype. Hereinafter, The semiconductor light emitting device according tothe (II)-th configuration of the present invention including thesepreferred configurations will be often referred to as “The semiconductorlight emitting device according to the (II)-th configuration of thepresent invention including the above-described preferredconfiguration.”

The semiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the impurity for causing the first compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the first compound semiconductor layer does not compete withthe substitution site of the impurity in the second compoundsemiconductor layer for causing the second compound semiconductor layerto have the second conductivity type, and

the impurity for causing the third compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the third compound semiconductor layer competes with thesubstitution site of the impurity in the fourth compound semiconductorlayer for causing the fourth compound semiconductor layer to have thesecond conductivity type. For convenience, this configuration will bereferred to as “the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention.” In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed. However, it is more preferable to employthe former multilayer structure.

The semiconductor light emitting device according to the ((II)-1)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-A)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-B)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-a)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is a site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-b)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-C)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-D)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-c)-th configuration of the present invention.”

In addition, the semiconductor light emitting device according to the((II)-1)-th configuration of the present invention may have thefollowing configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-1-d)-th configuration of the present invention.”

The above-described semiconductor light emitting devices according tothe ((II)-1-A)-th configuration, ((II)-1-a)-th configuration,((II)-1-B)-th configuration, ((II)-1-b)-th configuration, ((II)-1-C)-thconfiguration, ((II)-1-c)-th configuration, ((II)-1-D)-th configuration,and ((II)-1-d)-th configuration of the present invention, may have thefollowing configuration. Specifically,

the current block layer further includes a fifth compound semiconductorlayer of the second conductivity type,

the third compound semiconductor layer is sandwiched by the fourthcompound semiconductor layer and the fifth compound semiconductor layer,and

the impurity for causing the third compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the third compound semiconductor layer competes with thesubstitution site of the impurity in the fifth compound semiconductorlayer for causing the fifth compound semiconductor layer to have thesecond conductivity type. In this configuration, the multilayerstructure composed of the fourth compound semiconductor layer, the thirdcompound semiconductor layer, and the fifth compound semiconductor layerstacked in that order from the lower side may be employed.Alternatively, the multilayer structure composed of the fifth compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer stacked in that order from the lowerside may be employed. In addition, the following configuration is alsoavailable. Specifically,

the current block layer further includes a sixth compound semiconductorlayer of the first conductivity type,

the fourth compound semiconductor layer is sandwiched by the thirdcompound semiconductor layer and the sixth compound semiconductor layer,and

the impurity for causing the fourth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fourth compound semiconductor layer competes with thesubstitution site of the impurity in the sixth compound semiconductorlayer for causing the sixth compound semiconductor layer to have thefirst conductivity type. In this configuration, the multilayer structurecomposed of the third compound semiconductor layer, the fourth compoundsemiconductor layer, and the sixth compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the sixth compound semiconductor layer,the fourth compound semiconductor layer, and the third compoundsemiconductor layer stacked in that order from the lower side may beemployed.

In order to meet the above-described third need, the semiconductor lightemitting device according to the (II)-th configuration of the presentinvention including the above-described preferred configuration may havethe following configuration. Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the impurity for causing the first compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is carbon (C). For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-2-A)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-2-A)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the third compound semiconductor layer, the impurity inthe first burying layer, and the impurity in the second burying layer)is 3×2×4×1=24.

The first compound semiconductor layer containing a group VI impurity isthe part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed. However, it is more preferable to employthe former multilayer structure.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is carbon (C). For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-2-B)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-2-B)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe 2B-th compound semiconductor layer, the impurity in the 2A-thcompound semiconductor layer, the impurity in the fourth compoundsemiconductor layer, the impurity in the third compound semiconductorlayer, the impurity in the first burying layer, and the impurity in thesecond burying layer) is 2×3×4×1×4×2×4×1=768.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the impurity for causing the first compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group IV impurity. For convenience,this configuration will be referred to as “the semiconductor lightemitting device according to the ((II)-2-C)-th configuration of thepresent invention.” In the semiconductor light emitting device accordingto the ((II)-2-C)-th configuration of the present invention, the numberof combinations of (the impurity in the first compound semiconductorlayer, the impurity in the third compound semiconductor layer, theimpurity in the first burying layer, and the impurity in the secondburying layer) is 4×1×3×2=24.

The first compound semiconductor layer containing a group II impurity isthe part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed. However, it is more preferable to employthe former multilayer structure.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group IV impurity. For convenience,this configuration will be referred to as “the semiconductor lightemitting device according to the ((II)-2-D)-th configuration of thepresent invention.” In the semiconductor light emitting device accordingto the ((II)-2-D)-th configuration of the present invention, the numberof combinations of (the impurity in the 1A-th compound semiconductorlayer, the impurity in the 1B-th compound semiconductor layer, theimpurity in the 2B-th compound semiconductor layer, the impurity in the2A-th compound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the fourth compound semiconductorlayer, the impurity in the first burying layer, and the impurity in thesecond burying layer) is 1×4×3×2×1×3×3×2=432.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the impurity for causing the second compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is a group II impurity. For convenience,this configuration will be referred to as “the semiconductor lightemitting device according to the ((II)-3-a)-th configuration of thepresent invention.” In the semiconductor light emitting device accordingto the ((II)-3-a)-th configuration of the present invention, the numberof combinations of (the impurity in the second compound semiconductorlayer, the impurity in the fourth compound semiconductor layer, theimpurity in the first burying layer, and the impurity in the secondburying layer) is 4×1×1×4=16.

The second compound semiconductor layer containing a group II impurityis the part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed. However, it is more preferable to employthe former multilayer structure.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is a group II impurity. For convenience,this configuration will be referred to as “the semiconductor lightemitting device according to the ((II)-3-b)-th configuration of thepresent invention.” In the semiconductor light emitting device accordingto the ((II)-3-b)-th configuration of the present invention, the numberof combinations of (the impurity in the 1A-th compound semiconductorlayer, the impurity in the 1B-th compound semiconductor layer, theimpurity in the 2B-th compound semiconductor layer, the impurity in the2A-th compound semiconductor layer, the impurity in the fourth compoundsemiconductor layer, the impurity in the third compound semiconductorlayer, the impurity in the first burying layer, and the impurity in thesecond burying layer) is 2×3×4×1×1×3×1×4=288.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the impurity for causing the second compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group VI impurity. For convenience,this configuration will be referred to as “the semiconductor lightemitting device according to the ((II)-3-c)-th configuration of thepresent invention.” In the semiconductor light emitting device accordingto the ((II)-3-c)-th configuration of the present invention, the numberof combinations of (the impurity in the second compound semiconductorlayer, the impurity in the third compound semiconductor layer, theimpurity in the first burying layer, and the impurity in the secondburying layer) is 3×2×2×3=36.

The second compound semiconductor layer containing a group VI impurityis the part that is in contact with at least the active layer (includingwell layers and confinement layers), specifically. In thisconfiguration, the multilayer structure composed of the fourth compoundsemiconductor layer and the third compound semiconductor layer stackedin that order from the lower side may be employed. Alternatively, themultilayer structure composed of the third compound semiconductor layerand the fourth compound semiconductor layer stacked in that order fromthe lower side may be employed. However, it is more preferable to employthe former multilayer structure.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group VI impurity. For convenience,this configuration will be referred to as “the semiconductor lightemitting device according to the ((II)-3-d)-th configuration of thepresent invention.” In the semiconductor light emitting device accordingto the ((II)-3-d)-th configuration of the present invention, the numberof combinations of (the impurity in the 1A-th compound semiconductorlayer, the impurity in the 1B-th compound semiconductor layer, theimpurity in the 2B-th compound semiconductor layer, the impurity in the2A-th compound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the fourth compound semiconductorlayer, the impurity in the first burying layer, and the impurity in thesecond burying layer) is 1×4×3×2×2×4×2×3=1152.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have a configuration in which the impurityfor causing the first compound semiconductor layer (or the 1B-thcompound semiconductor layer) to have the first conductivity type isdifferent from the impurity for causing the third compound semiconductorlayer to have the first conductivity type. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-4-A)-th configuration of the presentinvention.”

The first compound semiconductor layer (or the 1B-th compoundsemiconductor layer) containing the impurity different from the impurityfor causing the third compound semiconductor layer to have the firstconductivity type is the part that is in contact with at least theactive layer, specifically. The active layer with which the firstcompound semiconductor layer is in contact encompasses well layers andconfinement layers. This applies also to the following description. Theprovision of the confinement layer allows light confinement and/orcarrier confinement. In this configuration, the multilayer structurecomposed of the fourth compound semiconductor layer and the thirdcompound semiconductor layer stacked in that order from the lower sidemay be employed. Alternatively, the multilayer structure composed of thethird compound semiconductor layer and the fourth compound semiconductorlayer stacked in that order from the lower side may be employed.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have a configuration in which the impurityfor causing the second compound semiconductor layer (or the 2B-thcompound semiconductor layer) to have the second conductivity type isdifferent from the impurity for causing the fourth compoundsemiconductor layer to have the second conductivity type. Forconvenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((II)-4-a)-thconfiguration of the present invention.”

The second compound semiconductor layer (or the 2B-th compoundsemiconductor layer) containing the impurity different from the impurityfor causing the fourth compound semiconductor layer to have the secondconductivity type is the part that is in contact with at least theactive layer (including well layers and confinement layers),specifically. In this configuration, the multilayer structure composedof the fourth compound semiconductor layer and the third compoundsemiconductor layer stacked in that order from the lower side may beemployed. Alternatively, the multilayer structure composed of the thirdcompound semiconductor layer and the fourth compound semiconductor layerstacked in that order from the lower side may be employed.

In addition, in order to meet the above-described third need, thesemiconductor light emitting device according to the (II)-thconfiguration of the present invention including the above-describedpreferred configuration may have the following configuration.Specifically,

the current block layer is formed of a multilayer structure arising fromsequential stacking of at least the fourth compound semiconductor layerof the second conductivity type and the third compound semiconductorlayer of the first conductivity type,

the impurity for causing the fourth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fourth compound semiconductor layer competes with thesubstitution site of the impurity in the third compound semiconductorlayer for causing the third compound semiconductor layer to have thefirst conductivity type, and competes with the substitution site of theimpurity in the first compound semiconductor layer for causing the firstcompound semiconductor layer to have the first conductivity type,

the impurity for causing the second compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the second compound semiconductor layer competes with thesubstitution site of the impurity in the third compound semiconductorlayer for causing the third compound semiconductor layer to have thefirst conductivity type, and

if a bypass channel that passes through the first compound semiconductorlayer, the current block layer, and the second compound semiconductorlayer is assumed, at least three pn junction interfaces formed of theinterfaces between the compound semiconductor layers exist in the bypasschannel. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((II)-5)-thconfiguration of the present invention.”

It is possible for the semiconductor light emitting device according tothe ((II)-5)-th configuration of the present invention to have a form inwhich the fourth compound semiconductor layer is in contact with theside surface of the first compound semiconductor layer and the thirdcompound semiconductor layer is in contact with the side surface of thesecond compound semiconductor layer. In this case, the bypass channel iscomposed of the first compound semiconductor layer, the fourth compoundsemiconductor layer, the third compound semiconductor layer, and thesecond compound semiconductor layer. The pn junction interfaces areformed of the following three interfaces: the interface between the sidesurface of the first compound semiconductor layer and the fourthcompound semiconductor layer; the interface between the fourth compoundsemiconductor layer and the third compound semiconductor layer; and theinterface between the third compound semiconductor layer and the sidesurface of the second compound semiconductor layer.

The semiconductor light emitting device according to the ((II)-5)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer, and

the impurity for causing the 1B-th compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the 1B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 1A-th compoundsemiconductor layer for causing the 1A-th compound semiconductor layerto have the first conductivity type, and does not compete with thesubstitution site of the impurity in the second compound semiconductorlayer for causing the second compound semiconductor layer to have thesecond conductivity type. In this case, the impurity for causing the1A-th compound semiconductor layer to have the first conductivity typeis such that the substitution site of the impurity in the 1A-th compoundsemiconductor layer competes with the substitution site of the impurityin the fourth compound semiconductor layer for causing the fourthcompound semiconductor layer to have the second conductivity type.

In the case of the configuration in which the 1B-th compoundsemiconductor layer is used, the relationship between the 1B-th compoundsemiconductor layer and the fourth compound semiconductor layer incontact with the side surface of the 1B-th compound semiconductor layeris such that their impurity substitution sites do not compete with eachother in some cases. In such a case, initially impurity diffusionbetween the 1B-th compound semiconductor layer and the fourth compoundsemiconductor layer will occur across this side surface part, and thenthe impurity diffusion will reach the third compound semiconductor layerincluded in the current block layer, so that a current leakage path ispossibly formed.

Therefore, for this case, the following configuration may be employed.Specifically, a sixth compound semiconductor layer of the firstconductivity type is provided under the fourth compound semiconductorlayer,

the impurity for causing the sixth compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the sixth compound semiconductor layer competes with thesubstitution site of the impurity in the first compound semiconductorlayer (or the 1A-th compound semiconductor layer) for causing the firstcompound semiconductor layer (or the 1A-th compound semiconductor layer)to have the first conductivity type, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer. Employing such aconfiguration eliminates the contact between the 1B-th compoundsemiconductor layer and the fourth compound semiconductor layer, whoseimpurity substitution sites do not compete with each other, and thus canprevent the impurity diffusion. In this case, the bypass channel iscomposed of the first compound semiconductor layer (the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer), thesixth compound semiconductor layer, the fourth compound semiconductorlayer, the third compound semiconductor layer, and the second compoundsemiconductor layer. The pn junction interfaces are formed of thefollowing three interfaces: the interface between the sixth compoundsemiconductor layer and the fourth compound semiconductor layer; theinterface between the fourth compound semiconductor layer and the thirdcompound semiconductor layer; and the interface between the thirdcompound semiconductor layer and the side surface of the second compoundsemiconductor layer.

In addition, in such a case, it is desirable to provide an impuritydiffusion barrier layer in the current block layer in order to preventthe occurrence of current leakage attributed to impurity diffusion fromthe 1B-th compound semiconductor layer into the current block layer.Specifically, a seventh compound semiconductor layer of the secondconductivity type whose impurity substitution site is different fromthat of the fourth compound semiconductor layer of the secondconductivity type is provided as the “impurity diffusion barrier layer.”More specifically, in the fourth compound semiconductor layer that isincluded in the current block layer and has the second conductivitytype, at least one impurity diffusion barrier layer having the secondconductivity type (e.g. the seventh compound semiconductor layer) isprovided. Furthermore, impurities are so selected that the substitutionsite of the impurity in the fourth compound semiconductor layer isdifferent from that of the impurity in the impurity diffusion barrierlayer (e.g. the seventh compound semiconductor layer if the number ofimpurity diffusion barrier layers is one). Employing such aconfiguration allows further-ensured prevention of the phenomenon that acurrent leakage path from the bypass channel is formed due to impuritydiffusion into the current block layer.

Furthermore, the semiconductor light emitting device according to the((II)-5)-th configuration of the present invention may have thefollowing configuration. Specifically,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer, and

the impurity for causing the 2B-th compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the 2B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 2A-th compoundsemiconductor layer for causing the 2A-th compound semiconductor layerto have the second conductivity type, and does not compete with thesubstitution site of the impurity in the first compound semiconductorlayer for causing the first compound semiconductor layer to have thefirst conductivity type. In this case, the impurity for causing the2A-th compound semiconductor layer to have the second conductivity typeis such that the substitution site of the impurity in the 2A-th compoundsemiconductor layer competes with the substitution site of the impurityin the third compound semiconductor layer for causing the third compoundsemiconductor layer to have the first conductivity type.

In the case of the configuration in which the 2B-th compoundsemiconductor layer is used, the relationship between the 2B-th compoundsemiconductor layer and the third compound semiconductor layer incontact with the side surface of the 2B-th compound semiconductor layeris such that their impurity substitution sites do not compete with eachother in some cases. In such a case, initially impurity diffusionbetween the 2B-th compound semiconductor layer and the third compoundsemiconductor layer will occur across this side surface part, and thenthe impurity diffusion will reach the fourth compound semiconductorlayer included in the current block layer, so that a current leakagepath is possibly formed.

Therefore, for this case, the following configuration may be employed.Specifically, a fifth compound semiconductor layer of the secondconductivity type is provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fifth compound semiconductor layer competes with thesubstitution site of the impurity in the second compound semiconductorlayer (or the 2A-th compound semiconductor layer) for causing the secondcompound semiconductor layer (or the 2A-th compound semiconductor layer)to have the second conductivity type, and

the fourth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer and the fifth compoundsemiconductor layer is in contact with the side surface of the secondcompound semiconductor layer (at least a part of the side surface of the2A-th compound semiconductor layer and all of the side surface of the2B-th compound semiconductor layer). Employing such a configurationeliminates the contact between the 2B-th compound semiconductor layerand the third compound semiconductor layer, whose impurity substitutionsites do not compete with each other, and thus can prevent the impuritydiffusion. In this case, the bypass channel is composed of the firstcompound semiconductor layer, the fourth compound semiconductor layer,the third compound semiconductor layer, the fifth compound semiconductorlayer, and the second compound semiconductor layer (the 2B-th compoundsemiconductor layer and the 2A-th compound semiconductor layer). The pnjunction interfaces are formed of the following three interfaces: theinterface between the side surface of the first compound semiconductorlayer and the fourth compound semiconductor layer; the interface betweenthe fourth compound semiconductor layer and the third compoundsemiconductor layer; and the interface between the third compoundsemiconductor layer and the fifth compound semiconductor layer.

In addition, in such a case, it is desirable to provide an impuritydiffusion barrier layer in the current block layer in order to preventthe occurrence of current leakage attributed to impurity diffusion fromthe 2B-th compound semiconductor layer into the current block layer.Specifically, an eighth compound semiconductor layer of the firstconductivity type whose impurity substitution site is different fromthat of the third compound semiconductor layer of the first conductivitytype is provided as the “impurity diffusion barrier layer.” Morespecifically, in the third compound semiconductor layer that is includedin the current block layer and has the first conductivity type, at leastone impurity diffusion barrier layer having the first conductivity type(e.g. the eighth compound semiconductor layer) is provided. Furthermore,impurities are so selected that the substitution site of the impurity inthe third compound semiconductor layer is different from that of theimpurity in the impurity diffusion barrier layer (e.g. the eighthcompound semiconductor layer if the number of impurity diffusion barrierlayers is one). Employing such a configuration allows further-ensuredprevention of the phenomenon that a current leakage path from the bypasschannel is formed due to impurity diffusion into the current blocklayer.

In the semiconductor light emitting device according to the ((II)-5)-thconfiguration of the present invention, the first compound semiconductorlayer, the second compound semiconductor layer, the fourth compoundsemiconductor layer, and the third compound semiconductor layer arecomposed of a III-V compound semiconductor. Alternatively, the 1A-thcompound semiconductor layer, the 1B-th compound semiconductor layer,the second compound semiconductor layer, the fourth compoundsemiconductor layer, and the third compound semiconductor layer arecomposed of a III-V compound semiconductor. Alternatively, the firstcompound semiconductor layer, the 2B-th compound semiconductor layer,the 2A-th compound semiconductor layer, the fourth compoundsemiconductor layer, and the third compound semiconductor layer arecomposed of a III-V compound semiconductor.

Furthermore, the following configuration can be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe first burying layer is the site occupied by a group III atom. Thesubstitution site of the impurity in the second burying layer is thesite occupied by a group V atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-5-A)-th configuration of the present invention.”It is possible to employ a form in which the fourth compoundsemiconductor layer is in contact with the side surface of the firstcompound semiconductor layer and the third compound semiconductor layeris in contact with the side surface of the second compound semiconductorlayer.

The semiconductor light emitting device according to the ((II)-5-A)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity,

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity,

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and the impurity forcausing the second burying layer to be the p-type as the secondconductivity type is carbon (C). For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-5-A-1)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-A-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, the impurity in the thirdcompound semiconductor layer, the impurity in the first burying layer,and the impurity in the second burying layer) is 2×4×4×2×4×1=256.

In addition, the semiconductor light emitting device according to the((II)-5-A)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity,

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group VI impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-5-A-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-A-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, the impurity in the thirdcompound semiconductor layer, the impurity in the first burying layer,and the impurity in the second burying layer) is 4×2×2×4×2×3=384.

Furthermore, the following configuration can be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group V atom. The substitution site of the impurity in thefirst burying layer is the site occupied by a group V atom. Thesubstitution site of the impurity in the second burying layer is thesite occupied by a group III atom. For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-5-a)-th configuration of the present invention.”It is possible to employ a form in which the fourth compoundsemiconductor layer is in contact with the side surface of the firstcompound semiconductor layer and the third compound semiconductor layeris in contact with the side surface of the second compound semiconductorlayer.

The semiconductor light emitting device according to the ((II)-5-a)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity,

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and the impurity for causing thesecond burying layer to be the p-type as the second conductivity type isa group II impurity. For convenience, this configuration will bereferred to as “the semiconductor light emitting device according to the((II)-5-a-1)-th configuration of the present invention.” In thesemiconductor light emitting device according to the ((II)-5-a-1)-thconfiguration of the present invention, the number of combinations of(the impurity in the first compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 3×1×1×3×1×4=36.

In addition, the semiconductor light emitting device according to the((II)-5-a)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity, and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group IV impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-5-a-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-a-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the second compound semiconductor layer, the impurity inthe fourth compound semiconductor layer, the impurity in the thirdcompound semiconductor layer, the impurity in the first burying layer,and the impurity in the second burying layer) is 1×3×3×1×3×2=54.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the 1A-th compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 1B-th compound semiconductor layer is the site occupied by a group Vatom. The substitution site of the impurity in the first burying layeris the site occupied by a group III atom. The substitution site of theimpurity in the second burying layer is the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((II)-5-B)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((II)-5-B)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity, and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and the impurity forcausing the second burying layer to be the p-type as the secondconductivity type is carbon (C). For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-5-B-1)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-B-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 2×3×4×4×2×4×1=768.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis a group IV impurity, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((II)-5-B)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity, and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group VI impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-5-B-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-B-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 4×1×2×2×4×2×3=384.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis a group II impurity, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the 1A-th compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group V atom. The substitution site of the impurity in the1B-th compound semiconductor layer is the site occupied by a group IIIatom. The substitution site of the impurity in the first burying layeris the site occupied by a group V atom. The substitution site of theimpurity in the second burying layer is the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((II)-5-b)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((II)-5-b)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and the impurity for causing thesecond burying layer to be the p-type as the second conductivity type isa group II impurity. For convenience, this configuration will bereferred to as “the semiconductor light emitting device according to the((II)-5-b-1)-th configuration of the present invention.” In thesemiconductor light emitting device according to the ((II)-5-b-1)-thconfiguration of the present invention, the number of combinations of(the impurity in the 1A-th compound semiconductor layer, the impurity inthe 1B-th compound semiconductor layer, the impurity in the secondcompound semiconductor layer, the impurity in the fourth compoundsemiconductor layer, the impurity in the third compound semiconductorlayer, the impurity in the first burying layer, and the impurity in thesecond burying layer) is 3×2×1×1×3×1×4=72.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis a group VI impurity, and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((II)-5-b)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity, and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group IV impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-5-b-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-b-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the 1A-th compound semiconductor layer,the impurity in the 1B-th compound semiconductor layer, the impurity inthe second compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 1×4×3×3×1×3×2=216.

In this case, the following configuration may be employed. Specifically,the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis carbon (C), and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the 2A-thcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 2B-th compound semiconductor layer is the site occupied by a group Vatom. The substitution site of the impurity in the first burying layeris the site occupied by a group III atom. The substitution site of theimpurity in the second burying layer is the site occupied by a group Vatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((II)-5-C)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((II)-5-C)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity,

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and the impurity forcausing the second burying layer to be the p-type as the secondconductivity type is carbon (C). For convenience, this configurationwill be referred to as “the semiconductor light emitting deviceaccording to the ((II)-5-C-1)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-C-1)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the 2B-th compound semiconductor layer, the impurity inthe 2A-th compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 2×1×4×4×2×4×1=256.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis a group II impurity, and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((II)-5-C)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group VI impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-5-C-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-C-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the 2B-th compound semiconductor layer, the impurity inthe 2A-th compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 4×3×2×2×4×2×3=1152.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis a group IV impurity, and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

Furthermore, the following configuration may be employed. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the 2A-thcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group V atom. The substitution site of the impurity in the2B-th compound semiconductor layer is the site occupied by a group IIIatom. The substitution site of the impurity in the first burying layeris the site occupied by a group V atom. The substitution site of theimpurity in the second burying layer is the site occupied by a group IIIatom. For convenience, this configuration will be referred to as “thesemiconductor light emitting device according to the ((II)-5-c)-thconfiguration of the present invention.”

The semiconductor light emitting device according to the ((II)-5-c)-thconfiguration of the present invention may have the followingconfiguration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C),

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and the impurity for causing thesecond burying layer to be the p-type as the second conductivity type isa group II impurity. For convenience, this configuration will bereferred to as “the semiconductor light emitting device according to the((II)-5-c-1)-th configuration of the present invention.” In thesemiconductor light emitting device according to the ((II)-5-c-1)-thconfiguration of the present invention, the number of combinations of(the impurity in the first compound semiconductor layer, the impurity inthe 2B-th compound semiconductor layer, the impurity in the 2A-thcompound semiconductor layer, the impurity in the fourth compoundsemiconductor layer, the impurity in the third compound semiconductorlayer, the impurity in the first burying layer, and the impurity in thesecond burying layer) is 3×4×1×1×3×1×4=144.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis carbon (C), and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

In addition, the semiconductor light emitting device according to the((II)-5-c)-th configuration of the present invention may have thefollowing configuration. Specifically,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity, and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group IV impurity. For convenience, thisconfiguration will be referred to as “the semiconductor light emittingdevice according to the ((II)-5-c-2)-th configuration of the presentinvention.” In the semiconductor light emitting device according to the((II)-5-c-2)-th configuration of the present invention, the number ofcombinations of (the impurity in the first compound semiconductor layer,the impurity in the 2B-th compound semiconductor layer, the impurity inthe 2A-th compound semiconductor layer, the impurity in the fourthcompound semiconductor layer, the impurity in the third compoundsemiconductor layer, the impurity in the first burying layer, and theimpurity in the second burying layer) is 1×2×3×3×1×3×2=108.

In this case, the following configuration may be employed. Specifically,the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer and the2A-th compound semiconductor layer to have the second conductivity typeis a group VI impurity, and

the fifth compound semiconductor layer is in contact with the sidesurface of the second compound semiconductor layer (at least a part ofthe side surface of the 2A-th compound semiconductor layer and all ofthe side surface of the 2B-th compound semiconductor layer), and thefourth compound semiconductor layer is in contact with the side surfaceof the first compound semiconductor layer.

In addition, in the semiconductor light emitting device according to the((II)-5)-th configuration of the present invention, a plurality ofcompound semiconductor layers may be provided between the fourthcompound semiconductor layer and the third compound semiconductor layerof the current block layer. Specifically, it is also possible to employa configuration in which at least a compound semiconductor layer of thefirst conductivity type and a compound semiconductor layer of the secondconductivity type are further sequentially stacked between the fourthcompound semiconductor layer and the third compound semiconductor layer.More specifically, if the first conductivity type is the n-type and thesecond conductivity type is the p-type, the current block layer may beformed based on a four-layer structure composed of the p-type fourthcompound semiconductor layer, an n-type compound semiconductor layer, ap-type compound semiconductor layer, and the n-type third compoundsemiconductor layer. Alternatively, the current block layer may beformed based on a six-layer structure composed of the p-type fourthcompound semiconductor layer, an n-type compound semiconductor layer, ap-type compound semiconductor layer, an n-type compound semiconductorlayer, a p-type compound semiconductor layer, and the n-type thirdcompound semiconductor layer. More alternatively, the current blocklayer may be formed based on an eight-layer structure composed of thep-type fourth compound semiconductor layer, an n-type compoundsemiconductor layer, a p-type compound semiconductor layer, an n-typecompound semiconductor layer, a p-type compound semiconductor layer, ann-type compound semiconductor layer, a p-type compound semiconductorlayer, and the n-type third compound semiconductor layer. Such amultilayer structure will be often represented as “the p-type fourthcompound semiconductor layer, (n-type compound semiconductor layer,p-type compound semiconductor layer)_(m), and the n-type third compoundsemiconductor layer (m=1, 2, 3, . . . ).” In addition, if the firstconductivity type is the p-type and the second conductivity type is then-type, the current block layer may be formed based on a multilayerstructure composed of the n-type fourth compound semiconductor layer,(p-type compound semiconductor layer, n-type compound semiconductorlayer)_(m), and the p-type third compound semiconductor layer (m=1, 2,3, . . . ). By thus forming the current block layer based on amultilayer structure, the phenomenon that a current leakage path fromthe bypass channel is formed can be prevented more surely even if arelative positional error between the light emitting part and thecurrent block layer occurred. It is desirable that the thickness of thecurrent block layer be not increased even when the current block layeris formed based on a multilayer structure. Furthermore, it is moredesirable that at least one pn interface (or np interface) between thecompound semiconductor layers included in the current block layer be incontact with the side surface of the active layer. This featuredecreases the area of the contact part with the side surface of thelight emitting part per one compound semiconductor layer included in thecurrent block layer, which results in an increase in the electricresistance. Consequently, leakage current is further suppressed and thusthe light output can be improved.

In the semiconductor light emitting device according to the ((II)-1)-thto ((II)-5)-th configurations including the semiconductor light emittingdevices according to the first to ((II)-5)-th configurations of thepresent invention (including the above-described various preferredconfigurations and forms) (hereinafter, these semiconductor lightemitting devices will be often referred to simply as “the semiconductorlight emitting device of the present invention” generically), it isdesirable for the first burying layer to have such a thickness or asmaller thickness that the first burying layer grown on the currentblock layer reaches the edge line composed of the top surface and theside surfaces of the light emitting part at the center part or both theend parts of the light emitting part at which the sectional shape of thelight emitting part obtained when the light emitting part is cut along avirtual plane perpendicular to the axis line is composed of the topsurface and both the side surfaces. That is, it is desirable for thefirst burying layer to have such a thickness or a smaller thickness asto cover the side surfaces of the light emitting part. On the otherhand, it is preferable for the second burying layer to have such athickness as to cover at least the side surfaces of the deposited layerformed on the top surface at both the end parts of the light emittingpart at the same timing as that of the current block layer. Furthermore,it is more preferable that these layers be so deposited to a largethickness that the top surface (apex) is sufficiently covered by themultilayer structure composed of the first burying layer and the secondburying layer with a thickness corresponding to such a distance thatlight generated by the active layer is not absorbed. In addition, it ispreferable to select materials having lower refractive indexes as thematerials of the first burying layer and the second burying layer.

Moreover, as a more desirable form regarding the contact surface withthe side surface of the light emitting part per one compoundsemiconductor layer included in the current block layer, it is desirablethat the width of the contact surface (the length of the contact surfacealong the vertical direction of the side surface of the light emittingpart) per one compound semiconductor layer included in the current blocklayer be equal to or smaller than the total thickness of the activelayer (the length of the active layer along the vertical direction ofthe side surface of the light emitting part) sandwiched between thefirst compound semiconductor layer (or the 1B-th compound semiconductorlayer) and the second compound semiconductor layer (or the 2B-thcompound semiconductor layer). In addition, if the active layer has aquantum well structure, it is desirable that the width of the contactsurface per one compound semiconductor layer included in the currentblock layer be equal to or smaller than the width of one well layer ofthe quantum well structure (the length of the well layer along thevertical direction of the side surface of the light emitting part). Sucha form involves the necessity that the thicknesses of the respectivecompound semiconductor layers included in the current block layer areset to very small values. Therefore, the related art has a problem thata part of the current block layer formed of the {311}B plane or ahigher-order crystal plane is annihilated or, conversely, the thicknessof this part is abnormally increased because of conductivity typeneutralization due to impurity mutual diffusion across the interface ofn-type compound semiconductor layer/p-type compound semiconductor layer(or p-type compound semiconductor layer/n-type compound semiconductorlayer) as described above. Consequently, according to the semiconductorlight emitting device of the ((II)-1)-th to ((II)-5)-th configurations,in achievement of desired conductivity types of the respective compoundsemiconductor layers included in the current block layer, the impuritycombination in consideration of the competition relationship of theimpurity substitution site is comprehensively determined from theviewpoint of current leakage suppression. This makes it possible torealize a structure that allows suppression of conductivity typeneutralization due to impurity mutual diffusion, enhancement in thecurrent block quality of the current block layer itself, and ensuredsuppression of leakage current from the side surface of the lightemitting part, even when the thicknesses of the respective compoundsemiconductor layers included in the current block layer are set to verysmall values.

In the semiconductor light emitting device of the above-describedpreferred configurations of the ((I)-1)-th to ((I)-5)-th configurationsand ((II)-1)-th to ((II)-5)-th configurations, the third compoundsemiconductor layer may be composed of a {311}B crystal plane regionthat extends from the side surface of the light emitting part; a {100}crystal plane region that extends along the major surface of thesubstrate; and a {h11}B crystal plane region (h is an integer equal toor larger than four) located between the {311}B crystal plane region andthe {100} crystal plane region. In addition, the fourth compoundsemiconductor layer may be composed of a {311}B crystal plane regionthat extends from the side surface of the light emitting part; a {100}crystal plane region that extends along the major surface of thesubstrate; and a {h11}B crystal plane region (h is an integer equal toor larger than four) located between the {311}B crystal plane region andthe {100} crystal plane region.

According to the semiconductor light emitting device of (II)-thconfiguration, in the burying layer located above the current blocklayer, the impurity for causing the second burying layer to have thesecond conductivity type is such that the substitution site of theimpurity in the second burying layer does not compete with thesubstitution site of the impurity in the third compound semiconductorlayer for causing the third compound semiconductor layer to have thefirst conductivity type. Therefore, the impurity for causing the secondburying layer to have the second conductivity type diffuses into thecompound semiconductor layer of the first conductivity type in thedeposited layer formed of the multilayer structure that is formed abovethe top surface at both the end parts of the light emitting part and hasthe same composition as that of the current block layer. This diffusionturns the compound semiconductor layer of the first conductivity type toa compound semiconductor layer of the second conductivity type. As aresult, all of the compound semiconductor layers located above the lightemitting part have the second conductivity type. Consequently, thedeposited layer having the same multilayer structure as that of thecurrent block layer does not exist above the top surface of themultilayer structure of the light emitting part, and thus it is possibleto surely avoid the occurrence of a problem that the light emissionefficiency of the semiconductor light emitting device is decreased and aproblem that the heat generation and the current consumption areincreased due to an increase in the electric resistance.

In the semiconductor light emitting device according to the ((II)-1)-thconfiguration of the present invention, the impurity for causing thethird compound semiconductor layer to have the first conductivity typeincluded in the current block layer is such that the substitution siteof the impurity in the third compound semiconductor layer competes withthe substitution site of the impurity in the fourth compoundsemiconductor layer for causing the fourth compound semiconductor layerto have the second conductivity type. Thus, impurity mutual diffusionhardly occurs between the n-type compound semiconductor layer and thep-type compound semiconductor layer of the current block layer. Thisallows avoidance of the occurrence of a problem that the effect of thecurrent block layer is unstable and thus leakage current is increaseddue to annihilation or thinning of the current block layer. Furthermore,the impurity for causing the first compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the first compound semiconductor layer does not compete withthe substitution site of the impurity in the second compoundsemiconductor layer for causing the second compound semiconductor layerto have the second conductivity type. Thus, the pn junction control,designed through intentional impurity mutual diffusion between the firstcompound semiconductor layer and the second compound semiconductorlayer, can be finely designed easily through adjustment of theconcentrations and doping positions of the impurities in the respectivelayers. This allows enhancement in the light emission characteristic.

In the semiconductor light emitting device according to the((II)-2-A)-th configuration of the present invention or the((II)-2-B)-th configuration of the present invention, the impurity forcausing the first compound semiconductor layer or the 1B-th compoundsemiconductor layer to be the n-type as the first conductivity type is agroup VI impurity, and the impurity for causing the third compoundsemiconductor layer to be the n-type as the first conductivity type is agroup IV impurity. Furthermore, in the semiconductor light emittingdevice according to the ((II)-2-C)-th configuration of the presentinvention or the ((II)-2-D)-th configuration of the present invention,the impurity for causing the first compound semiconductor layer or the1B-th compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity, and the impurity for causingthe third compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C). Furthermore, in the semiconductor lightemitting device according to the ((II)-3-a)-th configuration of thepresent invention or the ((II)-3-b)-th configuration of the presentinvention, the impurity for causing the second compound semiconductorlayer or the 2B-th compound semiconductor layer to be the p-type as thesecond conductivity type is a group II impurity, and the impurity forcausing the fourth compound semiconductor layer to be the p-type as thesecond conductivity type is carbon (C). In addition, in thesemiconductor light emitting device according to the ((II)-3-c)-thconfiguration of the present invention or the ((II)-3-d)-thconfiguration of the present invention, the impurity for causing thesecond compound semiconductor layer or the 2B-th compound semiconductorlayer to be the n-type as the second conductivity type is a group VIimpurity, and the impurity for causing the fourth compound semiconductorlayer to be the n-type as the second conductivity type is a group IVimpurity. Moreover, in the semiconductor light emitting device accordingto the ((II)-4-A)-th configuration of the present invention, theimpurity for causing the first compound semiconductor layer to have thefirst conductivity type is different from the impurity for causing thethird compound semiconductor layer to have the first conductivity type.In the semiconductor light emitting device according to the((II)-4-a)-th configuration of the present invention, the impurity forcausing the second compound semiconductor layer to have the secondconductivity type is different from the impurity for causing the fourthcompound semiconductor layer to have the second conductivity type.Employing these configurations and structures makes it possible toachieve configuration and structure in which impurity mutual diffusionhardly occurs between the n-type compound semiconductor layer and thep-type compound semiconductor layer of the current block layer. As aresult, it is possible to avoid the occurrence of a problem that theeffect of the current block layer is unstable and thus leakage currentis increased due to annihilation or thinning of the current block layer.

Furthermore, in the semiconductor light emitting device according to the((II)-5)-th configuration of the present invention, when a bypasschannel that passes through the first compound semiconductor layer, thecurrent block layer, and the second compound semiconductor layer isassumed, at least three pn junction interfaces formed of the interfacesbetween the compound semiconductor layers exist in the bypass channel.In addition, the impurity for causing a respective one of the compoundsemiconductor layers to have a predetermined conductivity type is suchthat the substitution site of the impurity in the respective one of thecompound semiconductor layers competes with the substitution site of theimpurity in the adjacent compound semiconductor layer for causing theadjacent compound semiconductor layer to have a predeterminedconductivity type. Thus, impurity mutual diffusion hardly occurs betweenthe n-type compound semiconductor layer and the p-type compoundsemiconductor layer of the current block layer. In addition, impuritymutual diffusion hardly occurs between the n-type compound semiconductorlayer and the p-type compound semiconductor layer of the current blocklayer and the p-type compound semiconductor layer and the n-typecompound semiconductor layer of the light emitting part. As a result, itis possible to avoid the occurrence of a problem that the effect of thecurrent block layer is unstable and thus leakage current is increaseddue to annihilation or thinning of the current block layer.

The semiconductor light emitting devices in the fifth to twenty-secondembodiments will be described in the followings.

Fifth Embodiment

The fifth embodiment relates to the ((I)-1)-th configuration, inparticular, ((I)-1-A)-th configuration of the present invention, the((I)-2-A)-th configuration of the present invention, and the((I)-4-A)-th configuration of the present invention. The conceptualdiagram of the semiconductor light emitting device of the fifthembodiment is shown in FIG. 7A. The schematic partial sectional view isshown in FIGS. 1A and 1B. In FIGS. 7A to 48B, “compound semiconductorlayer” is represented simply as “layer.” That is, for example, “firstlayer” means a first compound semiconductor layer. FIGS. 21A, 22A, 23A,24A, 25A, 26A, 27A, 28A, 29A, 30A, 31A, 32A, 33A, 34A, 35A, 36A, 37A,38A, 39A, 40A, 41A, 42A, 43A, 44A, 45A, 46A, 47A, and 48A are conceptualdiagrams of both the end parts of semiconductor light emitting devices.FIGS. 21B, 22B, 23B, 24B, 25B, 26B, 27B, 28B, 29B, 30B, 31B, 32B, 33B,34B, 35B, 36B, 37B, 38B, 39B, 40B, 41B, 42B, 43B, 44B, 45B, 46B, 47B,and 48B are conceptual diagrams of the center part of semiconductorlight emitting devices.

As shown in FIGS. 1A and 1B, the third compound semiconductor layer 43is formed on the fourth compound semiconductor layer 44. The pn junctioninterface between the fourth compound semiconductor layer 44 (p-type)and the third compound semiconductor layer 43 (n-type) thereon extendsalong the {311}B crystal plane, and the end part thereof is in contactwith the light emitting part 20 (in particular, the side surface of theactive layer 23). This forms two new junction interfaces. Specifically,a current path formed of the pnpn junction structure including thefollowing junction interfaces is formed: the pn junction interfacebetween the second compound semiconductor layers 22A and 22B and thethird compound semiconductor layer 43; the np junction interface betweenthe third compound semiconductor layer 43 and the fourth compoundsemiconductor layer 44; and the pn junction interface between the fourthcompound semiconductor layer 44 and the first compound semiconductorlayer 21. This is a desirable design as the current block structure.

Inversely with this multilayer structure, the positional relationshipbetween the third compound semiconductor layer 43 (n-type) and thefourth compound semiconductor layer 44 (p-type) may be reversed. In thiscase, the pn junction interface between the fourth compoundsemiconductor layer 44 (p-type) and the third compound semiconductorlayer 43 (n-type) thereunder extends along the {311}B crystal plane, andthe end part thereof is in contact with the light emitting part 20 (inparticular, the side surface of the active layer 23). This forms two newjunction interfaces. As a result, the following junction interfacesexist: the pp junction interface between the second compoundsemiconductor layers 22A and 22B and the fourth compound semiconductorlayer 44; the pn junction interface between the fourth compoundsemiconductor layer 44 and the third compound semiconductor layer 43;and the nn junction interface between the third compound semiconductorlayer 43 and the first compound semiconductor layer 21. Thus, a ppnnjunction structure arises due to the second compound semiconductorlayers 22A and 22B/the fourth compound semiconductor layer 44/the thirdcompound semiconductor layer 43/the first compound semiconductor layer21. However, by decreasing the junction area between the current blocklayer 40 and the light emitting part 20 (in particular, the nn junctionarea), a desired design as the current block structure can be obtainedthrough an increase in the resistance of the contact area.

Moreover, the impurity for causing the first compound semiconductorlayer 21 to have the first conductivity type (n-type) is such that thesubstitution site of the impurity in the first compound semiconductorlayer 21 does not compete with the substitution site of the impurity inthe second compound semiconductor layers 22A and 22B for causing thesecond compound semiconductor layers 22A and 22B to have the secondconductivity type (p-type). Furthermore, the impurity for causing thethird compound semiconductor layer 43 to have the first conductivitytype (n-type) is such that the substitution site of the impurity in thethird compound semiconductor layer 43 competes with the substitutionsite of the impurity in the fourth compound semiconductor layer 44 forcausing the fourth compound semiconductor layer 44 in contact with thethird compound semiconductor layer 43 to have the second conductivitytype (p-type). This applies also to the fourteenth embodiment to bedescribed later.

Specifically, when the semiconductor light emitting device of the fifthembodiment is represented based on the ((I)-1-A)-th configuration of thepresent invention, in the semiconductor light emitting device of thefifth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the third compound semiconductor layer43, and the fourth compound semiconductor layer 44 are composed of aIII-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group IIIatom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupIII atom.

Furthermore, when the semiconductor light emitting device of the fifthembodiment is represented based on the ((I)-2-A)-th configuration of thepresent invention, in the semiconductor light emitting device of thefifth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the third compound semiconductor layer43, and the fourth compound semiconductor layer 44 are composed of aIII-V compound semiconductor,

the impurity for causing the first compound semiconductor layer 21 to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the third compound semiconductor layer 43 to bethe n-type as the first conductivity type is a group IV impurity.

In addition, when the semiconductor light emitting device of the fifthembodiment is represented based on the ((I)-4-A)-th configuration of thepresent invention, in the semiconductor light emitting device of thefifth embodiment, the impurity for causing the first compoundsemiconductor layer 21 to have the first conductivity type (n-type) isdifferent from the impurity for causing the third compound semiconductorlayer 43 to have the first conductivity type (n-type).

Specifically, in the semiconductor light emitting device of the fifthembodiment, the respective layers have the configuration shown in Table1A or Table 1B shown below. The compound semiconductors of the firstcompound semiconductor layer 21, the second compound semiconductorlayers 22A and 22B, and the current block layer 40 have wider band gaps,i.e., lower refractive indexes, compared with the compoundsemiconductors of the active layer 23. In the example shown in Table 1A,the third compound semiconductor layer 43 is stacked on the fourthcompound semiconductor layer 44. In the example shown in Table 1B, thefourth compound semiconductor layer 44 is stacked on the third compoundsemiconductor layer 43. In the multilayer structures shown in Table 1Aand Table 1B, and Table 2A, Table 2B, Table 3A, Table 3B, Table 4A,Table 4B, Table 5A, Table 5B, Table 6A, Table 6B, Table 7A, Table 7B,Table 8A, Table 8B, Tables 9A to 9L, Table 11A, Table 11B, Table 12A,Table 12B, Table 13A, Table 13B, Table 14A, Table 14B, Table 15A, Table15B, Table 16A, Table 16B, Table 17A, Table 17B, Table 18A, Table 18B,and Tables 19A to 19L, which will be described later, an upper layercorresponds to a layer shown on an upper row in the table.

The active layer having the structure shown in the following table willbe represented as [Active layer-A] in Table 1A, Table 1B, Table 2A,Table 2B, Table 5A, Table 5B, Table 6A, Table 6B, Table 9A, Table 9C,Table 9E, Table 9G, Table 9I, Table 9K, Table 11A, Table 11B, Table 12A,Table 12B, Table 15A, Table 15B, Table 16A, Table 16B, Table 19A, Table19C, Table 19E, Table 19G, Table 191, and Table 19K. In this multilayerstructure, an upper layer corresponds to a layer shown on an upper rowin the table.

[Active Layer-A]

Confinement layer . . . p-Al_(0.3)Ga_(0.7)As:ZnConfinement layer . . . i-Al_(0.3)Ga_(0.7)AsMultiple quantum well structure . . .

i-Al_(0.1)Ga_(0.9)As (well layer)

i-Al_(0.3)Ga_(0.7)As (barrier layer), and

i-Al_(0.1)Ga_(0.9)As (well layer)

Confinement layer . . . i-Al_(0.3)Ga_(0.7)AsConfinement layer . . . n-Al_(0.3)Ga_(0.7)As:Se

The active layer having the structure shown in the following table willbe represented as [Active layer-B] in Table 3A, Table 3B, Table 4A,Table 4B, Table 7A, Table 7B, Table 8A, Table 8B, Table 9B, Table 9D,Table 9F, Table 9H, Table 9J, Table 9L, Table 13A, Table 13B, Table 14A,Table 14B, Table 17A, Table 17B, Table 18A, Table 18B, Table 19B, Table19D, Table 19F, Table 19H, Table 19J, and Table 19L. In this multilayerstructure, an upper layer corresponds to a layer shown on an upper rowin the table.

[Active Layer-B]

Confinement layer . . . n-Al_(0.3)Ga_(0.7)As:SeConfinement layer . . . i-Al_(0.3)Ga_(0.7)AsMultiple quantum well structure . . .

i-Al_(0.1)Ga_(0.9)As (well layer)

i-Al_(0.3)Ga_(0.7)As (barrier layer), and

i-Al_(0.1)Ga_(0.9)As (well layer)

Confinement layer . . . i-Al_(0.3)Ga_(0.7)AsConfinement layer . . . p-Al_(0.3)Ga_(0.7)As:Zn

TABLE 1A (Configuration of light emitting part) Second compoundsemiconductor layer 22B . . . p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A . . . p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 .. . [Active layer -A] First compound semiconductor layer 21 . . .n-Al_(0.4)Ga_(0.6)As: Se (Current block layer) Burying layer 31A . . .p-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductor layer 43 . . .n-Al_(0.47)Ga_(0.53)As: Si Fourth compound semiconductor layer 44 . . .p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer 30 . . .p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 . . . p-GaAs: Zn (orC) (Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer 43 and the buryinglayer 31 (the partial portion of the burying layer 31 in the vicinity ofthe interface with the third compound semiconductor layer 43 correspondsto this fifth compound semiconductor layer).

TABLE 1B (Configuration of light emitting part) Second compoundsemiconductor layer 22B . . . p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A . . . p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 .. . [Active layer -A] First compound semiconductor layer 21 . . .n-Al_(0.4)Ga_(0.6)As: Se (Current block layer) Burying layer 31 . . .p-Al_(0.47)Ga_(0.53)As: Zn Fourth compound semiconductor layer 44 . . .p-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductor layer 43 . . .n-Al_(0.47)Ga_(0.53)As: Si Adjustment layer 30 . . .p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 . . . p-GaAs: Zn (orC) (Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The burying layer 31 isformed subsequently to the fourth compound semiconductor layer 44 in acontinuous manner, and a boundary does not exist between the buryinglayer 31 and the fourth compound semiconductor layer 44 substantially.(Note 3) It is also possible to consider that a fifth compoundsemiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn is formedbetween the third compound semiconductor layer 43 and the adjustmentlayer 30 (the partial portion of the adjustment layer 30 in the vicinityof the interface with the third compound semiconductor layer 43corresponds to this fifth compound semiconductor layer).

The third compound semiconductor layer 43 as a part of the current blocklayer is composed of

the {311}B crystal plane region (specifically, the (31-1)B plane and the((II)-3-11)B plane) that extends from the side surface of the lightemitting part 20,

the {100} crystal plane region that extends along the major surface ofthe substrate 10, and

the {h11}B crystal plane region (specifically, the (h1-1)B plane and the(h-11)B plane, h is an integer equal to or larger than four) that islocated between the {311}B crystal plane region and the {100} crystalplane region. The {h11}B crystal plane region (h is an integer equal toor larger than four) will be referred to as a high-order crystal planeregion, for convenience.

Furthermore, the fourth compound semiconductor layer 44 formed under thethird compound semiconductor layer 43 is also composed of

similarly to the third compound semiconductor layer 43, the {311}Bcrystal plane region that extends from the side surface of the lightemitting part 20,

the {100} crystal plane region that extends along the major surface ofthe substrate 10, and

the high-order crystal plane region that is located between the {311}Bcrystal plane region and the {100} crystal plane region.

Also in the semiconductor light emitting devices of the sixth totwenty-second embodiments to be described later, the third compoundsemiconductor layer 43 and the fourth compound semiconductor layer 44have the same structures as the above-described structures basically,except for the vertical positional relationship between the layers.

In [Step-120] of the first embodiment, the current block layer 40composed of the fourth compound semiconductor layer 44 and the thirdcompound semiconductor layer 43 is formed based on MOCVD. The fourthcompound semiconductor layer 44 is composed ofp-Al_(0.47)Ga_(0.53)As:Zn, and the third compound semiconductor layer 43is composed of n-Al_(0.47)Ga_(0.53)As:Si. Specifically, the substitutionsite of the impurity (Si) for causing the third compound semiconductorlayer 43 to have the first conductivity type (n-type) in the thirdcompound semiconductor layer 43 is the site occupied by a group IIIatom. Furthermore, the substitution site of the impurity (Zn) forcausing the fourth compound semiconductor layer 44 to have the secondconductivity type (p-type) in the fourth compound semiconductor layer 44is also the site occupied by a group III atom. That is, the impurity forcausing the third compound semiconductor layer 43 to have the firstconductivity type is such that the substitution site of the impurity inthe third compound semiconductor layer 43 competes with the substitutionsite of the impurity in the fourth compound semiconductor layer 44 forcausing the fourth compound semiconductor layer 44 to have the secondconductivity type. This applies also to the fourteenth embodiment to bedescribed later.

Therefore, when the fourth compound semiconductor layer 44 and theburying layer 31 are deposited after the deposition of the thirdcompound semiconductor layer 43, impurity mutual diffusion between thethird compound semiconductor layer 43 and the fourth compoundsemiconductor layer 44 of the current block layer 40 hardly occurs. Inaddition, impurity mutual diffusion between the current block layer 40and the upper and lower layers in contact with the current block layer40 also hardly occurs. This allows avoidance of the occurrence of aproblem that the effect of the current block layer 40 is unstable andthus leakage current is increased due to annihilation or thinning of thecurrent block layer 40. This applies also to the fourteenth embodimentto be described later.

Moreover, the impurity for causing the first compound semiconductorlayer 21 to have the first conductivity type (n-type) is such that thesubstitution site of the impurity in the first compound semiconductorlayer 21 (the site occupied by a group V atom) does not compete with thesubstitution site of the impurity in the second compound semiconductorlayers 22A and 22B (the site occupied by a group III atom) for causingthe second compound semiconductor layers 22A and 22B to have the secondconductivity type (p-type). Thus, the pn junction control, designedthrough intentional impurity mutual diffusion between the first compoundsemiconductor layer 21 and the second compound semiconductor layers 22Aand 22B, can be finely designed easily through adjustment of theconcentrations and doping positions of the impurities in the respectivelayers. This allows enhancement in the light emission characteristic.This applies also to the fourteenth embodiment to be described later.

In the semiconductor light emitting device of the fifth embodiment, theside parts (side surfaces) of the active layer 23 formed above theunderlying layer 11 are covered by the current block layer 40, whoserefractive index is lower than that of the active layer 23. Furthermore,the active layer 23 is vertically sandwiched by the first compoundsemiconductor layer 21 and the second compound semiconductor layers 22Aand 22B, whose refractive indexes are lower than that of the activelayer 23. Consequently, the upper and lower regions and the side regionsof the active layer 23 provide a complete light confinement structure.Moreover, above the exposed surface of the substrate 10, in the vicinityof the side surface of the active layer 23, a so-called thyristorstructure is formed due to the p-n-p-n structure (the p-type buryinglayer 31—the n-type third compound semiconductor layer 43—the p-typefourth compound semiconductor layer 44, the p-type adjustment layer 30(the p-type second compound semiconductor layer 22B), and the p-typesecond compound semiconductor layer 22A—the n-type first compoundsemiconductor layer 21). Therefore, current flowing above the exposedsurface of the substrate 10 is prevented, which focuses the current onthe active layer 23 and thus allows lower threshold current. It is alsopossible to regard the p-type adjustment layer 30 as the p-type fourthcompound semiconductor layer 44 or the p-type second compoundsemiconductor layer 22B. This applies also to the sixth, ninth, tenth,fourteenth, fifteenth, eighteenth, and nineteenth embodiments to bedescribed later.

Although FIGS. 49 and 50 or FIGS. 55 and 56 described later show thestructure in which the end surfaces of the current block layer 40 are incontact with the side surfaces of the active layer 23, the end surfacesof the current block layer 40 may be in contact with the side surfacesof the second compound semiconductor layers 22A and 22B, or may be incontact with the side surfaces of the first compound semiconductor layer21. Also with this structure, leakage current can be suppressed inpractical use. However, regarding the positions of the end surfaces ofthe current block layer 40 in contact with the light emitting part 20,it is desirable that at least a part of the current block layer 40 be incontact with the side surface of the active layer 23. This applies alsoto the sixth to twenty-second embodiments to be described later.

The third compound semiconductor layer 43, which is composed of the{311}B crystal plane region that extends from the side surface of thelight emitting part 20, the {100} crystal plane region that extendsalong the major surface of the substrate 10, and the high-order crystalplane region located between the {311}B crystal plane region and the{100} crystal plane region is formed. As a result, the third compoundsemiconductor layer 43 having stable (uniform) impurity concentrationcan be formed (stacked), which makes it easy to adjust the concentrationbalance with respective to the layer that is in contact with the thirdcompound semiconductor layer 43 and has the different conductivity type.Thus, the current block layer 40 having high current block capabilitycan be obtained. Moreover, because the third compound semiconductorlayer 43 having stable impurity concentration can be formed (stacked),when the third compound semiconductor layer 43 is formed on the fourthcompound semiconductor layer 44, or when the fourth compoundsemiconductor layer 44 is formed on the third compound semiconductorlayer 43, it is possible to more surely avoid the occurrence of aproblem that the effect of the current block layer 40 is unstable andthus leakage current is increased due to annihilation or thinning of thecurrent block layer 40.

Sixth Embodiment

The sixth embodiment is a modification of the fifth embodiment, andrelates to the ((I)-1-B)-th configuration of the present invention andthe ((I)-2-B)-th configuration of the present invention.

Specifically, as shown in FIG. 8A as a conceptual diagram, when thesemiconductor light emitting device of the sixth embodiment isrepresented based on the ((I)-1-B)-th configuration of the presentinvention, in the semiconductor light emitting device of the sixthembodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, and a fourth compoundsemiconductor layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom.

Furthermore, when the semiconductor light emitting device of the sixthembodiment is represented based on the ((I)-2-B)-th configuration of thepresent invention, in the semiconductor light emitting device of thesixth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity.

More specifically, in the semiconductor light emitting device of thesixth embodiment, the respective layers have the configuration shown inTable 2A or Table 2B shown below. In the example shown in Table 2A, thethird compound semiconductor layer is stacked on the fourth compoundsemiconductor layer. In the example shown in Table 2B, the fourthcompound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 2A (Configuration of light emitting part) 2A-th compoundsemiconductor layer . . . p-Al_(0.4)Ga_(0.6)As: C 2B-th compoundsemiconductor layer . . . p-Al_(0.4)Ga_(0.6)As: Zn Active layer . . .[Active layer -A] 1B-th compound semiconductor layer . . .n-Al_(0.4)Ga_(0.6)As: Se 1A-th compound semiconductor layer . . .n-Al_(0.4)Ga_(0.6)As: Si (Current block layer) Burying layer . . .p-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductor layer . . .n-Al_(0.47)Ga_(0.53)As: Si Fourth compound semiconductor layer . . .p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer . . . Al_(0.47)Ga_(0.53)As:Zn (Whole) Contact layer . . . p-GaAs: Zn (or C) (Note 1) The adjustmentlayer is formed subsequently to the 2A-th compound semiconductor layer.(Note 2) The fourth compound semiconductor layer is formed subsequentlyto the adjustment layer in a continuous manner, and a boundary does notexist between the fourth compound semiconductor layer and the adjustmentlayer substantially. (Note 3) It is also possible to consider that afifth compound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As:Zn is formed between the third compound semiconductor layer and theburying layer.

TABLE 2B (Configuration of light emitting part) 2A-th compoundsemiconductor layer . . . p-Al_(0.4)Ga_(0.6)As: C 2B-th compoundsemiconductor layer . . . p-Al_(0.4)Ga_(0.6)As: Zn Active layer . . .[Active layer -A] 1B-th compound semiconductor layer . . .n-Al_(0.4)Ga_(0.6)As: Se 1A-th compound semiconductor layer . . .n-Al_(0.4)Ga_(0.6)As: Si (Current block layer) Burying layer . . .p-Al_(0.47)Ga_(0.53)As: Zn Fourth compound semiconductor layer . . .p-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductor layer . . .n-Al_(0.47)Ga_(0.53)As: Si Adjustment layer . . .p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer . . . p-GaAs: Zn (or C)(Note 1) The adjustment layer is formed subsequently to the 2A-thcompound semiconductor layer. (Note 2) The burying layer is formedsubsequently to the fourth compound semiconductor layer in a continuousmanner, and a boundary does not exist between the burying layer and thefourth compound semiconductor layer substantially. (Note 3) It is alsopossible to consider that a fifth compound semiconductor layer composedof p-Al_(0.47)Ga_(0.53)As: Zn is formed between the third compoundsemiconductor layer and the adjustment layer (the partial portion of theadjustment layer in the vicinity of the interface with the thirdcompound semiconductor layer corresponds to this fifth compoundsemiconductor layer).

In the sixth embodiment, the substitution site of the impurity in the1A-th compound semiconductor layer is the site occupied by a group IIIatom, and the substitution site of the impurity in the fourth compoundsemiconductor layer is also the site occupied by a group III atom.Furthermore, the substitution site of the impurity in the third compoundsemiconductor layer in contact with the fourth compound semiconductorlayer is also the site occupied by a group III atom. Specifically, theimpurity for causing the 1A-th compound semiconductor layer to have thefirst conductivity type (n-type) is such that the substitution site ofthe impurity in the 1A-th compound semiconductor layer (the siteoccupied by a group III atom) competes with the substitution site of theimpurity in the fourth compound semiconductor layer (the site occupiedby a group III atom) for causing the fourth compound semiconductor layerto have the second conductivity type (p-type), and competes also withthe substitution site of the impurity for causing the third compoundsemiconductor layer in contact with the fourth compound semiconductorlayer to have the first conductivity type (n-type) (the site occupied bya group III atom). Therefore, when the fourth compound semiconductorlayer is deposited, impurity mutual diffusion hardly occurs between thefourth compound semiconductor layer of the current block layer and the1A-th compound semiconductor layer, and between the fourth compoundsemiconductor layer and the third compound semiconductor layer. Thus,the current block layer having high reliability can be formed. Thesuppression of the impurity mutual diffusion in the current block layercomposed of the fourth compound semiconductor layer and the thirdcompound semiconductor layer is effective for the {311}B plane and thehigh-order plane. On the other hand, the suppression of the impuritymutual diffusion across the interface between the fourth compoundsemiconductor layer and the 1A-th compound semiconductor layer iseffective for the {111}B plane interface. This applies also to thefifteenth embodiment described later.

Seventh Embodiment

The seventh embodiment is also a modification of the fifth embodiment,and relates to the ((I)-1-C)-th configuration of the present invention,the ((I)-2-C)-th configuration of the present invention, and the((I)-4-A)-th configuration of the present invention. In the seventhembodiment and the eighth embodiment to be described later, theconductivity types are reversed from those in the fifth embodiment. Thatis, in the seventh embodiment and the eighth embodiment to be describedlater, the first conductivity type is the p-type and the secondconductivity type is the n-type. The schematic partial sectional view isshown in FIGS. 6A and 6B.

Specifically, as shown in FIG. 9A as a conceptual diagram, when thesemiconductor light emitting device of the seventh embodiment isrepresented based on the ((I)-1-C)-th configuration of the presentinvention, in the semiconductor light emitting device of the seventhembodiment,

a first compound semiconductor layer 21, second compound semiconductorlayers 22A and 22B, and a current block layer 40 (a third compoundsemiconductor layer 43 and a fourth compound semiconductor layer 44) arecomposed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupV atom.

Furthermore, when the semiconductor light emitting device of the seventhembodiment is represented based on the ((I)-2-C)-th configuration of thepresent invention, in the semiconductor light emitting device of theseventh embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, and the current block layer 40 (thethird compound semiconductor layer 43 and the fourth compoundsemiconductor layer 44) are composed of a III-V compound semiconductor,

the impurity for causing the first compound semiconductor layer 21 to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the third compound semiconductor layer 43 to bethe p-type as the first conductivity type is carbon (C).

Furthermore, when the semiconductor light emitting device of the seventhembodiment is represented based on the ((I)-4-A)-th configuration of thepresent invention, in the semiconductor light emitting device of theseventh embodiment, the impurity for causing the first compoundsemiconductor layer 21 to have the first conductivity type (p-type) isdifferent from the impurity for causing the third compound semiconductorlayer 43 to have the first conductivity type (p-type).

More specifically, in the semiconductor light emitting device of theseventh embodiment, the respective layers have the configuration shownin Table 3A or Table 3B shown below. In the example shown in Table 3A,the third compound semiconductor layer 43 is stacked on the fourthcompound semiconductor layer 44. In the example shown in Table 3B, thefourth compound semiconductor layer 44 is stacked on the third compoundsemiconductor layer 43.

TABLE 3A (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Burying layer 31A n-Al_(0.47)Ga_(0.53)As: Se Thirdcompound semiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: C Fourthcompound semiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Se Adjustmentlayer 30 n-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer 32 n-GaAs: Se(or Si) (Note 1) The adjustment layer 30 is formed subsequently to thesecond compound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer 43 and the buryinglayer 31 (the partial portion of the burying layer 31 in the vicinity ofthe interface with the third compound semiconductor layer 43 correspondsto this fifth compound semiconductor layer).

TABLE 3B (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Burying layer 31 n-Al_(0.47)Ga_(0.53)As: Se Fourthcompound semiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Se Thirdcompound semiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: C Adjustmentlayer 30 n-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer 32 n-GaAs: Se(or Si) (Note 1) The adjustment layer 30 is formed subsequently to thesecond compound semiconductor layer 22B. (Note 2) The burying layer 31is formed subsequently to the fourth compound semiconductor layer 44 ina continuous manner, and a boundary does not exist between the buryinglayer 31 and the fourth compound semiconductor layer 44 substantially.(Note 3) It is also possible to consider that a fifth compoundsemiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Zn is formedbetween the third compound semiconductor layer 43 and the adjustmentlayer 30 (the partial portion of the adjustment layer 30 in the vicinityof the interface with the third compound semiconductor layer 43corresponds to this fifth compound semiconductor layer).

Also in the seventh embodiment, in a step similar to [Step-130] of thefirst embodiment, e.g. the adjustment layer 30 and the current blocklayer 40 composed of the fourth compound semiconductor layer 44 and thethird compound semiconductor layer 43 are sequentially formed based onMOCVD. The third compound semiconductor layer 43 is composed ofp-Al_(0.47)Ga_(0.53)As:C, and the fourth compound semiconductor layer 44is composed of n-Al_(0.47)Ga_(0.53)As:Se. Specifically, the substitutionsite of the impurity (C) for causing the third compound semiconductorlayer 43 to have the first conductivity type (p-type) in the thirdcompound semiconductor layer 43 is the site occupied by a group V atom.Furthermore, the substitution site of the impurity (Se) for causing thefourth compound semiconductor layer 44 to have the second conductivitytype (n-type) in the fourth compound semiconductor layer 44 is also thesite occupied by a group V atom. That is, the impurity for causing thethird compound semiconductor layer 43 to have the first conductivitytype is such that the substitution site of the impurity in the thirdcompound semiconductor layer 43 competes with the substitution site ofthe impurity in the fourth compound semiconductor layer 44 for causingthe fourth compound semiconductor layer 44 to have the secondconductivity type. This applies also to the sixteenth embodimentdescribed later.

Therefore, when the fourth compound semiconductor layer 44 is depositedafter the deposition of the third compound semiconductor layer 43, orwhen the third compound semiconductor layer 43 is deposited after thedeposition of the fourth compound semiconductor layer 44, impuritymutual diffusion between the third compound semiconductor layer 43 andthe fourth compound semiconductor layer 44 of the current block layer 40hardly occurs. This allows avoidance of the occurrence of a problem thatthe effect of the current block layer 40 is unstable and thus leakagecurrent is increased due to annihilation or thinning of the currentblock layer 40. This applies also to the sixteenth embodiment describedlater.

Moreover, the impurity for causing the first compound semiconductorlayer 21 to have the first conductivity type (p-type) is such that thesubstitution site of the impurity in the first compound semiconductorlayer 21 (the site occupied by a group III atom) does not compete withthe substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B (the site occupied by a group V atom)for causing the second compound semiconductor layers 22A and 22B to havethe second conductivity type (n-type). Thus, the pn junction control,designed through intentional impurity mutual diffusion between the firstcompound semiconductor layer 21 and the second compound semiconductorlayers 22A and 22B, can be finely designed easily through adjustment ofthe concentrations and doping positions of the impurities in therespective layers. This allows enhancement in the light emissioncharacteristic. This applies also to the sixteenth embodiment describedlater.

Also in the semiconductor light emitting device of the seventhembodiment, the side parts (side surfaces) of the active layer 23 formedabove the underlying layer 11 are covered by the current block layer 40,whose refractive index is lower than that of the active layer 23.Furthermore, the active layer 23 is vertically sandwiched by the firstcompound semiconductor layer 21 and the second compound semiconductorlayers 22A and 22B, whose refractive indexes are lower than that of theactive layer 23. Consequently, the upper and lower regions and the sideregions of the active layer 23 provide a complete light confinementstructure. Moreover, above the exposed surface of the substrate 10, inthe vicinity of the side surface of the active layer 23, a so-calledthyristor structure is formed due to the n-p-n-p structure (the n-typeburying layer 31—the p-type third compound semiconductor layer 43—then-type fourth compound semiconductor layer 44—the n-type adjustmentlayer 30 (the n-type second compound semiconductor layer 22B) and then-type second compound semiconductor layer 22A—the p-type first compoundsemiconductor layer 21). Therefore, current flowing above the exposedsurface of the substrate 10 is prevented, which focuses the current onthe active layer 23 and thus allows lower threshold current. It is alsopossible to regard the n-type adjustment layer 30 as the n-type fourthcompound semiconductor layer 44 or the n-type second compoundsemiconductor layer 22B. This applies also to the eighth, eleventh,twelfth, sixteenth, seventeenth, twentieth, and twenty-first embodimentsto be described later.

In the MOCVD at the time of the deposition of the third compoundsemiconductor layer 43, a methyl group or an ethyl group obtainedthrough decomposition of the source gas for a group III atom may beintentionally used as the source gas for the addition of carbon (C).Alternatively, in the MOCVD at the time of the deposition of the thirdcompound semiconductor layer 43, a CBr₄ or a CCl₄ gas may be added. Thisapplies also to the sixteenth embodiment described later.

Eighth Embodiment

The eighth embodiment is a modification of the fifth embodiment and theseventh embodiment, and relates to the ((I)-1-D)-th configuration of thepresent invention and the ((I)-2-D)-th configuration of the presentinvention.

Specifically, as shown in FIG. 10A as a conceptual diagram, when thesemiconductor light emitting device of the eighth embodiment isrepresented based on the ((I)-1-D)-th configuration of the presentinvention, in the semiconductor light emitting device of the eighthembodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, and a fourth compoundsemiconductor layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom.

Furthermore, when the semiconductor light emitting device of the eighthembodiment is represented based on the ((I)-2-D)-th configuration of thepresent invention, in the semiconductor light emitting device of theeighth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer, are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity.

More specifically, in the semiconductor light emitting device of theeighth embodiment, the respective layers have the configuration shown inTable 4A or Table 4B shown below. In the example shown in Table 4A, thethird compound semiconductor layer is stacked on the fourth compoundsemiconductor layer. In the example shown in Table 4B, the fourthcompound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 4A (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer n-GaAs: Se (or Si)(Note 1) The adjustment layer is formed subsequently to the 2A-thcompound semiconductor layer. (Note 2) The fourth compound semiconductorlayer is formed subsequently to the adjustment layer in a continuousmanner, and a boundary does not exist between the fourth compoundsemiconductor layer and the adjustment layer substantially. (Note 3) Itis also possible to consider that a fifth compound semiconductor layercomposed of n-Al_(0.47)Ga_(0.53)As: Zn is formed between the thirdcompound semiconductor layer and the burying layer (the partial portionof the burying layer in the vicinity of the interface with the thirdcompound semiconductor layer corresponds to this fifth compoundsemiconductor layer).

TABLE 4B (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer n-GaAs: Se (or Si)(Note 1) The adjustment layer is formed subsequently to the 2A-thcompound semiconductor layer. (Note 2) The burying layer is formedsubsequently to the fourth compound semiconductor layer in a continuousmanner, and a boundary does not exist between the burying layer and thefourth compound semiconductor layer substantially. (Note 3) It is alsopossible to consider that a fifth compound semiconductor layer composedof n-Al_(0.47)Ga_(0.53)As: Zn is formed between the third compoundsemiconductor layer and the adjustment layer (the partial portion of theadjustment layer in the vicinity of the interface with the thirdcompound semiconductor layer corresponds to this fifth compoundsemiconductor layer).

In the eighth embodiment and the seventeenth embodiment described later,if a multilayer structure that includes the fourth compoundsemiconductor layer as the lower layer and the third compoundsemiconductor layer as the upper layer as shown in Table 4B or Table 14Bis formed unlike the examples shown in FIG. 10A or FIGS. 24A and 24B,the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom, and thesubstitution site of the impurity in the fourth compound semiconductorlayer is also the site occupied by a group V atom. Furthermore, thesubstitution site of the impurity in the third compound semiconductorlayer in contact with the fourth compound semiconductor layer is alsothe site occupied by a group V site. That is, the impurity for causingthe 1A-th compound semiconductor layer to have the first conductivitytype (p-type) is such that the substitution site of the impurity in the1A-th compound semiconductor layer (the site occupied by a group V atom)competes with the substitution site of the impurity in the fourthcompound semiconductor layer (the site occupied by a group V atom) forcausing the fourth compound semiconductor layer to have the secondconductivity type (n-type), and competes also with the substitution siteof the impurity for causing the third compound semiconductor layer incontact with the fourth compound semiconductor layer to have the firstconductivity type (p-type) (the site occupied by a group V atom).Therefore, when the fourth compound semiconductor layer is deposited,impurity mutual diffusion hardly occurs between the fourth compoundsemiconductor layer of the current block layer and the 1A-th compoundsemiconductor layer, and between the fourth compound semiconductor layerand the third compound semiconductor layer. Thus, the current blocklayer having high reliability can be formed. This allows more effectiveavoidance of the occurrence of a problem that the effect of the currentblock layer 40 is unstable and thus leakage current is increased due toannihilation or thinning of the current block layer 40.

Ninth Embodiment

The ninth embodiment relates to the ((I)-1-a)-th configuration of thepresent invention, the ((I)-3-a)-th configuration of the presentinvention, and the ((I)-4-a)-th configuration of the present invention.

Specifically, as shown in FIG. 7B as a conceptual diagram, when thesemiconductor light emitting device of the ninth embodiment isrepresented based on the ((I)-1-a)-th configuration of the presentinvention, in the semiconductor light emitting device of the ninthembodiment,

a first compound semiconductor layer 21, second compound semiconductorlayers 22A and 22B, and a current block layer 40 (a fourth compoundsemiconductor layer 44 and a third compound semiconductor layer 43) arecomposed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group IIIatom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupV atom. Schematic partial sectional views of the semiconductor lightemitting device of the ninth embodiment are the same as those shown inFIGS. 1A and 1B.

When the semiconductor light emitting device of the ninth embodiment isrepresented based on the ((I)-3-a)-th configuration of the presentinvention, in the semiconductor light emitting device of the ninthembodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, and the current block layer 40 (thefourth compound semiconductor layer 44 and the third compoundsemiconductor layer 43) are composed of a III-V compound semiconductor,

the impurity for causing the second compound semiconductor layers 22Aand 22B to be the p-type as the second conductivity type is a group IIimpurity,

the impurity for causing the fourth compound semiconductor layer 44 tobe the p-type as the second conductivity type is carbon (C).

Furthermore, when the semiconductor light emitting device of the ninthembodiment is represented based on the ((I)-4-a)-th configuration of thepresent invention, in the semiconductor light emitting device of theninth embodiment, the impurity for causing the second compoundsemiconductor layers 22A and 22B to have the second conductivity type(p-type) is different from the impurity for causing the fourth compoundsemiconductor layer 44 to have the second conductivity type (p-type).

More specifically, in the semiconductor light emitting device of theninth embodiment, the respective layers have the configuration shown inTable 5A or Table 5B shown below. In the example shown in Table 5A, thethird compound semiconductor layer 43 is stacked on the fourth compoundsemiconductor layer 44. In the example shown in Table 5B, the fourthcompound semiconductor layer 44 is stacked on the third compoundsemiconductor layer 43.

TABLE 5A (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Burying layer 31 p-Al_(0.47)Ga_(0.53)As: Zn Thirdcompound semiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Se Fourthcompound semiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: C Adjustmentlayer 30 p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn(or C) (Note 1) The adjustment layer 30 is formed subsequently to thesecond compound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer 43 and the buryinglayer 31 (the partial portion of the burying layer 31 in the vicinity ofthe interface with the third compound semiconductor layer 43 correspondsto this fifth compound semiconductor layer).

TABLE 5B (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Burying layer 31 p-Al_(0.47)Ga_(0.53)As: Zn Fourthcompound semiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: C Third compoundsemiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Se Adjustment layer 30p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The burying layer 31 isformed subsequently to the fourth compound semiconductor layer 44 in acontinuous manner, and a boundary does not exist between the buryinglayer 31 and the fourth compound semiconductor layer 44 substantially.(Note 3) It is also possible to consider that a fifth compoundsemiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn is formedbetween the third compound semiconductor layer 43 and the adjustmentlayer 30 (the partial portion of the adjustment layer 30 in the vicinityof the interface with the third compound semiconductor layer 43corresponds to this fifth compound semiconductor layer).

Also in the ninth embodiment, in a step similar to [Step-130] of thefirst embodiment, e.g. the adjustment layer 30 and the current blocklayer 40 composed of the fourth compound semiconductor layer 44 and thethird compound semiconductor layer 43 are sequentially formed based onMOCVD. The fourth compound semiconductor layer 44 is composed ofp-Al_(0.47)Ga_(0.53)As:C, and the third compound semiconductor layer 43is composed of n-Al_(0.47)Ga_(0.53)As:Se. Specifically, the substitutionsite of the impurity (Se) for causing the third compound semiconductorlayer 43 to have the first conductivity type (n-type) in the thirdcompound semiconductor layer 43 is the site occupied by a group V atom.Furthermore, the substitution site of the impurity (C) for causing thefourth compound semiconductor layer 44 to have the second conductivitytype (p-type) in the fourth compound semiconductor layer 44 is also thesite occupied by a group V atom. That is, the impurity for causing thethird compound semiconductor layer 43 to have the first conductivitytype is such that the substitution site of the impurity in the thirdcompound semiconductor layer 43 competes with the substitution site ofthe impurity in the fourth compound semiconductor layer for causing thefourth compound semiconductor layer 44 to have the second conductivitytype. This applies also to the eighteenth embodiment described later.

Therefore, when the third compound semiconductor layer 43 is depositedafter the deposition of the fourth compound semiconductor layer 44, orwhen the fourth compound semiconductor layer 44 is deposited after thedeposition of the third compound semiconductor layer 43, impurity mutualdiffusion between the third compound semiconductor layer 43 and thefourth compound semiconductor layer 44 of the current block layer 40hardly occurs. This allows avoidance of the occurrence of a problem thatthe effect of the current block layer 40 is unstable and thus leakagecurrent is increased due to annihilation or thinning of the currentblock layer 40. This applies also to the eighteenth embodiment describedlater.

Moreover, the impurity for causing the first compound semiconductorlayer 21 to have the first conductivity type (n-type) is such that thesubstitution site of the impurity in the first compound semiconductorlayer 21 (the site occupied by a group V atom) does not compete with thesubstitution site of the impurity in the second compound semiconductorlayers 22A and 22B (the site occupied by a group III atom) for causingthe second compound semiconductor layers 22A and 22B to have the secondconductivity type (p-type). Thus, the pn junction control, designedthrough intentional impurity mutual diffusion between the first compoundsemiconductor layer 21 and the second compound semiconductor layers 22Aand 22B, can be finely designed easily through adjustment of theconcentrations and doping positions of the impurities in the respectivelayers. This allows enhancement in the light emission characteristic.This applies also to the eighteenth embodiment described later.

Also in the semiconductor light emitting device of the ninth embodiment,the side parts (side surfaces) of the active layer 23 formed above theunderlying layer 11 are covered by the current block layer 40, whoserefractive index is lower than that of the active layer 23. Furthermore,the active layer 23 is vertically sandwiched by the first compoundsemiconductor layer 21 and the second compound semiconductor layers 22Aand 22B, whose refractive indexes are lower than that of the activelayer 23. Consequently, the upper and lower regions and the side regionsof the active layer 23 provide a complete light confinement structure.Moreover, above the exposed surface of the substrate 10, in the vicinityof the side surface of the active layer 23, a so-called thyristorstructure is formed due to the p-n-p-n structure (the p-type buryinglayer 31—the n-type third compound semiconductor layer 43—the p-typefourth compound semiconductor layer 44, the p-type adjustment layer 30(the p-type second compound semiconductor layer 22B), and the p-typesecond compound semiconductor layer 22A—the n-type first compoundsemiconductor layer 21). Therefore, current flowing above the exposedsurface of the substrate 10 is prevented, which focuses the current onthe active layer 23 and thus allows lower threshold current. Thisapplies also to the eighteenth embodiment described later.

Tenth Embodiment

The tenth embodiment is a modification of the ninth embodiment, andrelates to the ((I)-1-b)-th configuration of the present invention andthe ((I)-3-b)-th configuration of the present invention.

Specifically, as shown in FIG. 8B as a conceptual diagram, when thesemiconductor light emitting device of the tenth embodiment isrepresented based on the ((I)-1-b)-th configuration of the presentinvention, in the semiconductor light emitting device of the tenthembodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, and a fourth compoundsemiconductor layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom.

Furthermore, when the semiconductor light emitting device of the tenthembodiment is represented based on the ((I)-3-b)-th configuration of thepresent invention, in the semiconductor light emitting device of thetenth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, and thefourth compound semiconductor layer are composed of a III-V compoundsemiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C).

More specifically, in the semiconductor light emitting device of thetenth embodiment, the respective layers have the configuration shown inTable 6A or Table 6B shown below. In the example shown in Table 6A, thethird compound semiconductor layer is stacked on the fourth compoundsemiconductor layer. In the example shown in Table 6B, the fourthcompound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 6A (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] 1B-thcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 1A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Current block layer)Burying layer p-Al_(0.47)Ga_(0.53)As: C Third compound semiconductorlayer n-Al_(0.47)Ga_(0.53)As: Se Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: C Adjustment layer p-Al_(0.47)Ga_(0.53)As: C(Whole) Contact layer p-GaAs: C (or Zn) (Note 1) The adjustment layer isformed subsequently to the 2A-th compound semiconductor layer. (Note 2)The fourth compound semiconductor layer is formed subsequently to theadjustment layer in a continuous manner, and a boundary does not existbetween the fourth compound semiconductor layer and the adjustment layersubstantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer and the buryinglayer.

TABLE 6B (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] 1B-thcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 1A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Current block layer)Burying layer p-Al_(0.47)Ga_(0.53)As: C Fourth compound semiconductorlayer p-Al_(0.47)Ga_(0.53)As: C Third compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Se Adjustment layer p-Al_(0.47)Ga_(0.53)As: C(Whole) Contact layer p-GaAs: C (or Zn) (Note 1) The adjustment layer isformed subsequently to the 2A-th compound semiconductor layer. (Note 2)The burying layer is formed subsequently to the fourth compoundsemiconductor layer in a continuous manner, and a boundary does notexist between the burying layer and the fourth compound semiconductorlayer substantially. (Note 3) It is also possible to consider that afifth compound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As:Zn is formed between the third compound semiconductor layer and theadjustment layer (the partial portion of the adjustment layer in thevicinity of the interface with the third compound semiconductor layercorresponds to this fifth compound semiconductor layer).

Eleventh Embodiment

The eleventh embodiment is also a modification of the ninth embodiment,and relates to the ((I)-1-c)-th configuration of the present invention,the ((I)-3-c)-th configuration of the present invention, and the((I)-4-a)-th configuration of the present invention. In the eleventhembodiment and the twelfth embodiment to be described later, theconductivity types are reversed from those in the ninth embodiment. Thatis, in the eleventh embodiment and the twelfth embodiment to bedescribed later, the first conductivity type is the p-type and thesecond conductivity type is the n-type.

Specifically, as shown in FIG. 9B as a conceptual diagram, when thesemiconductor light emitting device of the eleventh embodiment isrepresented based on the ((I)-1-c)-th configuration of the presentinvention, in the semiconductor light emitting device of the eleventhembodiment,

a first compound semiconductor layer 21, second compound semiconductorlayers 22A and 22B, and a current block layer 40 (a third compoundsemiconductor layer 43 and a fourth compound semiconductor layer 44) arecomposed of a III-V compound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupIII atom. Schematic partial sectional views of the semiconductor lightemitting device of the eleventh embodiment are the same as those shownin FIGS. 6A and 6B.

Furthermore, when the semiconductor light emitting device of theeleventh embodiment is represented based on the ((I)-3-c)-thconfiguration of the present invention, in the semiconductor lightemitting device of the eleventh embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, and the current block layer 40 (thethird compound semiconductor layer 43 and the fourth compoundsemiconductor layer 44) are composed of a III-V compound semiconductor,

the impurity for causing the second compound semiconductor layers 22Aand 22B to be the n-type as the second conductivity type is a group VIimpurity,

the impurity for causing the fourth compound semiconductor layer 44 tobe the n-type as the second conductivity type is a group IV impurity.

Furthermore, when the semiconductor light emitting device of theeleventh embodiment is represented based on the ((I)-4-a)-thconfiguration of the present invention, in the semiconductor lightemitting device of the eleventh embodiment, the impurity for causing thesecond compound semiconductor layers 22A and 22B to have the secondconductivity type (n-type) is different from the impurity for causingthe fourth compound semiconductor layer 44 to have the secondconductivity type (n-type).

More specifically, in the semiconductor light emitting device of theeleventh embodiment, the respective layers have the configuration shownin Table 7A or Table 7B shown below. In the example shown in Table 7A,the third compound semiconductor layer 43 is stacked on the fourthcompound semiconductor layer 44. In the example shown in Table 7B, thefourth compound semiconductor layer 44 is stacked on the third compoundsemiconductor layer 43.

TABLE 7A (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Burying layer 31 n-Al_(0.47)Ga_(0.53)As: Si Thirdcompound semiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: Zn Fourthcompound semiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Si Adjustmentlayer 30 n-Al_(0.47)Ga_(0.53)As: Si (Whole) Contact layer 32 n-GaAs: Si(or Se) (Note 1) The adjustment layer 30 is formed subsequently to thesecond compound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer 43 and the buryinglayer 31 (the partial portion of the burying layer 31 in the vicinity ofthe interface with the third compound semiconductor layer 43 correspondsto this fifth compound semiconductor layer).

TABLE 7B (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Burying layer 31 n-Al_(0.47)Ga_(0.53)As: Si Fourthcompound semiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Si Thirdcompound semiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: Zn Adjustmentlayer 30 n-Al_(0.47)Ga_(0.53)As: Si (Whole) Contact layer 32 n-GaAs: Si(or Se) (Note 1) The adjustment layer 30 is formed subsequently to thesecond compound semiconductor layer 22B. (Note 2) The burying layer 31is formed subsequently to the fourth compound semiconductor layer 44 ina continuous manner, and a boundary does not exist between the buryinglayer 31 and the fourth compound semiconductor layer 44 substantially.(Note 3) It is also possible to consider that a fifth compoundsemiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Zn is formedbetween the third compound semiconductor layer 43 and the adjustmentlayer 30 (the partial portion of the adjustment layer 30 in the vicinityof the interface with the third compound semiconductor layer 43corresponds to this fifth compound semiconductor layer).

Also in the eleventh embodiment, in a step similar to [Step-130] of thefirst embodiment, e.g. the adjustment layer 30 and the current blocklayer 40 composed of the fourth compound semiconductor layer 44 and thethird compound semiconductor layer 43 are sequentially formed based onMOCVD. The third compound semiconductor layer 43 is composed ofp-Al_(0.47)Ga_(0.53)As:Zn, and the fourth compound semiconductor layer44 is composed of n-Al_(0.47)Ga_(0.53)As:Si. Specifically, thesubstitution site of the impurity (Zn) for causing the third compoundsemiconductor layer 43 to have the first conductivity type (p-type) inthe third compound semiconductor layer 43 is the site occupied by agroup III atom. Furthermore, the substitution site of the impurity (Si)for causing the fourth compound semiconductor layer 44 to have thesecond conductivity type (n-type) in the fourth compound semiconductorlayer 44 is also the site occupied by a group III atom. That is, theimpurity for causing the third compound semiconductor layer 43 to havethe first conductivity type is such that the substitution site of theimpurity in the third compound semiconductor layer 43 competes with thesubstitution site of the impurity in the fourth compound semiconductorlayer for causing the fourth compound semiconductor layer 44 to have thesecond conductivity type. This applies also to the twentieth embodimentdescribed later.

Therefore, when the fourth compound semiconductor layer 44 is depositedafter the deposition of the third compound semiconductor layer 43, orwhen the third compound semiconductor layer 43 is deposited after thedeposition of the fourth compound semiconductor layer 44, impuritymutual diffusion between the third compound semiconductor layer 43 andthe fourth compound semiconductor layer 44 of the current block layer 40hardly occurs. This allows avoidance of the occurrence of a problem thatthe effect of the current block layer 40 is unstable and thus leakagecurrent is increased due to annihilation or thinning of the currentblock layer 40. This applies also to the twentieth embodiment describedlater.

Moreover, the impurity for causing the first compound semiconductorlayer 21 to have the first conductivity type (p-type) is such that thesubstitution site of the impurity in the first compound semiconductorlayer 21 (the site occupied by a group III atom) does not compete withthe substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B (the site occupied by a group V atom)for causing the second compound semiconductor layers 22A and 22B to havethe second conductivity type (n-type). Thus, the pn junction control,designed through intentional impurity mutual diffusion between the firstcompound semiconductor layer 21 and the second compound semiconductorlayers 22A and 22B, can be finely designed easily through adjustment ofthe concentrations and doping positions of the impurities in therespective layers. This allows enhancement in the light emissioncharacteristic. This applies also to the twentieth embodiment describedlater.

Also in the semiconductor light emitting device of the eleventhembodiment, the side parts (side surfaces) of the active layer 23 formedabove the underlying layer 11 are covered by the current block layer 40,whose refractive index is lower than that of the active layer 23.Furthermore, the active layer 23 is vertically sandwiched by the firstcompound semiconductor layer 21 and the second compound semiconductorlayers 22A and 22B, whose refractive indexes are lower than that of theactive layer 23. Consequently, the upper and lower regions and the sideregions of the active layer 23 provide a complete light confinementstructure. Moreover, above the exposed surface of the substrate 10, inthe vicinity of the side surface of the active layer 23, a so-calledthyristor structure is formed due to the n-p-n-p structure (the n-typeburying layer 31—the p-type third compound semiconductor layer 43—then-type fourth compound semiconductor layer 44—the n-type adjustmentlayer 30 (the n-type second compound semiconductor layer 22B) and then-type second compound semiconductor layer 22A—the p-type first compoundsemiconductor layer 21). Therefore, current flowing above the exposedsurface of the substrate 10 is prevented, which focuses the current onthe active layer 23 and thus allows lower threshold current. Thisapplies also to the twentieth embodiment described later.

The third compound semiconductor layer 43, which is composed of the{311}B crystal plane region that extends from the side surface of thelight emitting part 20, the {100} crystal plane region that extendsalong the major surface of the substrate 10, and the high-order crystalplane region located between the {311}B crystal plane region and the{100} crystal plane region is formed. As a result, the third compoundsemiconductor layer 43 having stable (uniform) impurity concentrationcan be formed (stacked), which makes it easy to adjust the concentrationbalance with respective to the layer that is in contact with the thirdcompound semiconductor layer 43 and has the different conductivity type.Thus, the current block layer 40 having high current block capabilitycan be obtained. Moreover, because the third compound semiconductorlayer 43 having stable impurity concentration can be formed (stacked),when the fourth compound semiconductor layer 44 is formed on the thirdcompound semiconductor layer 43, or when the third compoundsemiconductor layer 43 is formed on the fourth compound semiconductorlayer 44, it is possible to more surely avoid the occurrence of aproblem that the effect of the current block layer 40 is unstable andthus leakage current is increased due to annihilation or thinning of thecurrent block layer 40. This applies also to the twentieth embodimentdescribed later.

Twelfth Embodiment

The twelfth embodiment is a modification of the ninth embodiment and theeleventh embodiment, and relates to the ((I)-1-d)-th configuration ofthe present invention and the ((I)-3-d)-th configuration of the presentinvention.

Specifically, as shown in FIG. 10B as a conceptual diagram, when thesemiconductor light emitting device of the twelfth embodiment isrepresented based on the ((I)-1-d)-th configuration of the presentinvention, in the semiconductor light emitting device of the twelfthembodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, a fourth compoundsemiconductor layer, a first burying layer, and a second burying layerare composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom.

Furthermore, when the semiconductor light emitting device of the twelfthembodiment is represented based on the ((I)-3-d)-th configuration of thepresent invention, in the semiconductor light emitting device of thetwelfth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity.

More specifically, in the semiconductor light emitting device of thetwelfth embodiment, the respective layers have the configuration shownin Table 8A or Table 8B shown below. In the example shown in Table 8A,the third compound semiconductor layer is stacked on the fourth compoundsemiconductor layer. In the example shown in Table 8B, the fourthcompound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 8A (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Si Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Adjustment layern-Al_(0.47)Ga_(0.53)As: Si (Whole) Contact layer n-GaAs: Si (or Se)(Note 1) The adjustment layer is formed subsequently to the 2A-thcompound semiconductor layer. (Note 2) The fourth compound semiconductorlayer is formed subsequently to the adjustment layer in a continuousmanner, and a boundary does not exist between the fourth compoundsemiconductor layer and the adjustment layer substantially. (Note 3) Itis also possible to consider that a fifth compound semiconductor layercomposed of n-Al_(0.47)Ga_(0.53)As: Zn is formed between the thirdcompound semiconductor layer and the burying layer (the partial portionof the burying layer in the vicinity of the interface with the thirdcompound semiconductor layer corresponds to this fifth compoundsemiconductor layer).

TABLE 8B (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layern-Al_(0.47)Ga_(0.53)As: Si (Whole) Contact layer n-GaAs: Si (or Se)(Note 1) The adjustment layer is formed subsequently to the 2A-thcompound semiconductor layer. (Note 2) The burying layer is formedsubsequently to the fourth compound semiconductor layer in a continuousmanner, and a boundary does not exist between the burying layer and thefourth compound semiconductor layer substantially. (Note 3) It is alsopossible to consider that a fifth compound semiconductor layer composedof n-Al_(0.47)Ga_(0.53)As: Zn is formed between the third compoundsemiconductor layer and the adjustment layer (the partial portion of theadjustment layer in the vicinity of the interface with the thirdcompound semiconductor layer corresponds to this fifth compoundsemiconductor layer).

Thirteenth Embodiment

The thirteenth embodiment relates to the semiconductor light emittingdevice according to the ((I)-5)-th configuration (specifically, the((I)-5-A-1)-th configuration) of the present invention. As shown in FIG.11A as a conceptual diagram, in FIG. 1A as a schematic partial sectionalview, and in FIG. 1B as an enlarged schematic partial sectional view,the semiconductor light emitting device of the thirteenth embodimentincludes

(A) a light emitting part 20 formed of a multilayer structure arisingfrom sequential stacking of a first compound semiconductor layer 21 of afirst conductivity type (n-type, in the thirteenth embodiment), anactive layer 23, and a second compound semiconductor layer 22 of asecond conductivity type (p-type, in the thirteenth embodiment), and

(B) a current block layer 40 provided in contact with the side surfaceof the light emitting part 20.

The current block layer 40 is formed of a multilayer structure arisingfrom sequential stacking of at least a fourth compound semiconductorlayer 44 of the second conductivity type and a third compoundsemiconductor layer 43 of the first conductivity type. The impurity forcausing the fourth compound semiconductor layer 44 to have the secondconductivity type is such that the substitution site of the impurity inthe fourth compound semiconductor layer 44 competes with thesubstitution site of the impurity in the third compound semiconductorlayer 43 for causing the third compound semiconductor layer 43 to havethe first conductivity type, and competes with the substitution site ofthe impurity in the first compound semiconductor layer 21 for causingthe first compound semiconductor layer 21 to have the first conductivitytype. Furthermore, the impurity for causing the second compoundsemiconductor layer 22 to have the second conductivity type is such thatthe substitution site of the impurity in the second compoundsemiconductor layer 22 competes with the substitution site of theimpurity in the third compound semiconductor layer 43 for causing thethird compound semiconductor layer 43 to have the first conductivitytype. In addition, when a bypass channel that passes through the firstcompound semiconductor layer 21, the current block layer 40, and thesecond compound semiconductor layer 22 is assumed, at least three pnjunction interfaces formed of the interfaces between the respectivecompound semiconductor layers exist in the bypass channel.

The fourth compound semiconductor layer 44 is in contact with the sidesurface of the first compound semiconductor layer 21, and the thirdcompound semiconductor layer 43 is in contact with the side surface ofthe second compound semiconductor layer 22. Specifically, the bypasschannel is composed of the first compound semiconductor layer 21, thefourth compound semiconductor layer 44, the third compound semiconductorlayer 43, and the second compound semiconductor layer 22. The pnjunction interfaces are formed of the following three interfaces: theinterface between the side surface of the first compound semiconductorlayer 21 and the fourth compound semiconductor layer 44; the interfacebetween the fourth compound semiconductor layer 44 and the thirdcompound semiconductor layer 43; and the interface between the thirdcompound semiconductor layer 43 and the side surface of the secondcompound semiconductor layer 22.

Also in the semiconductor light emitting device of the thirteenthembodiment, the first compound semiconductor layer 21, the secondcompound semiconductor layer 22, the fourth compound semiconductor layer44, and the third compound semiconductor layer 43 are composed of aIII-V compound semiconductor. Furthermore, as described later, a 1A-thcompound semiconductor layer 21A, a 1B-th compound semiconductor layer21B, the second compound semiconductor layer 22, the fourth compoundsemiconductor layer 44, and the third compound semiconductor layer 43are composed of a III-V compound semiconductor. In addition, the firstcompound semiconductor layer 21, a 2A-th compound semiconductor layer22A, a 2B-th compound semiconductor layer 22B, the fourth compoundsemiconductor layer 44, and the third compound semiconductor layer 43are composed of a III-V compound semiconductor.

In the thirteenth embodiment, the substitution site of the impurity inthe first compound semiconductor layer 21, the substitution site of theimpurity in the second compound semiconductor layer 22, the substitutionsite of the impurity in the fourth compound semiconductor layer 44, andthe substitution site of the impurity in the third compoundsemiconductor layer 43 are the site occupied by a group III atom. Theimpurity for causing the first compound semiconductor layer 21 and thethird compound semiconductor layer 43 to be the n-type as the firstconductivity type is a group IV impurity (specifically, silicon, Si).The impurity for causing the second compound semiconductor layer 22 andthe fourth compound semiconductor layer 44 to be the p-type as thesecond conductivity type is a group II impurity (specifically, zinc,Zn).

More specifically, in the semiconductor light emitting device of thethirteenth embodiment, the respective layers have the configurationshown in Table 9A shown below.

TABLE 9A (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Si(Current block layer) Burying layer 31 p-Al_(0.47)Ga_(0.53)As: Zn Thirdcompound semiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Si Fourthcompound semiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: Zn Adjustmentlayer 30 p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn(or C) (Note 1) The adjustment layer 30 is formed subsequently to thesecond compound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between theadjustment layer 30 and the fourth compound semiconductor layer 44substantially.

In the example shown in FIG. 1B, the third compound semiconductor layer43 is formed on the fourth compound semiconductor layer 44. The pnjunction interface between the third compound semiconductor layer 43(n-type) and the fourth compound semiconductor layer 44 (p-type)thereunder extends along the {311}B crystal plane, and the end partthereof is in contact with the light emitting part 20 (in particular,the side surface of the active layer 23). This forms two new junctioninterfaces. Specifically, a current path formed of the pnpn junctionstructure including the following junction interfaces is formed: the pnjunction interface between the second compound semiconductor layers 22Aand 22B and the third compound semiconductor layer 43; the np junctioninterface between the third compound semiconductor layer 43 and thefourth compound semiconductor layer 44; and the pn junction interfacebetween the fourth compound semiconductor layer 44 and the firstcompound semiconductor layer 21. This is a desirable design as thecurrent block structure. This applies also to the twenty-secondembodiment described later.

Moreover, in the thirteenth embodiment, the substitution site of theimpurity in the first compound semiconductor layer 21, the substitutionsite of the impurity in the fourth compound semiconductor layer 44, thesubstitution site of the impurity in the third compound semiconductorlayer 43, and the substitution site of the impurity in the secondcompound semiconductor layer 22 are the site occupied by a group IIIatom. That is, the impurity for causing the first compound semiconductorlayer 21 to have the first conductivity type (n-type) is such that thesubstitution site of the impurity in the first compound semiconductorlayer 21 (the site occupied by a group III atom) competes with thesubstitution site of the impurity in the fourth compound semiconductorlayer 44 (the site occupied by a group III atom) for causing the fourthcompound semiconductor layer 44 to have the second conductivity type(p-type). Furthermore, the impurity for causing the third compoundsemiconductor layer 43 to have the first conductivity type (n-type) issuch that the substitution site of the impurity in the third compoundsemiconductor layer 43 (the site occupied by a group III atom) competeswith the substitution site of the impurity in the fourth compoundsemiconductor layer 44 (the site occupied by a group III atom) forcausing the fourth compound semiconductor layer 44 to have the secondconductivity type (p-type). In addition, the impurity for causing thesecond compound semiconductor layer 22 to have the second conductivitytype (p-type) is such that the substitution site of the impurity in thesecond compound semiconductor layer 22 (the site occupied by a group IIIatom) competes with the substitution site of the impurity in the thirdcompound semiconductor layer 43 (the site occupied by a group III atom)for causing the third compound semiconductor layer 43 to have the firstconductivity type (n-type). Therefore, when the fourth compoundsemiconductor layer 44 is deposited, impurity mutual diffusion hardlyoccurs between the fourth compound semiconductor layer 44 of the currentblock layer 40 and the first compound semiconductor layer 21.Furthermore, when the third compound semiconductor layer 43 isdeposited, impurity mutual diffusion hardly occurs between the thirdcompound semiconductor layer 43 and the fourth compound semiconductorlayer 44 of the current block layer 40, and between the third compoundsemiconductor layer 43 and the second compound semiconductor layer 22.Thus, the current block layer 40 having high reliability can be formed.Specifically, it is possible to surely avoid the occurrence of a problemthat the effect of the current block layer 40 is unstable and thusleakage current is increased due to annihilation or thinning of thecurrent block layer 40. This applies also to the twenty-secondembodiment described later.

Except for the above-described points, the semiconductor light emittingdevice of the thirteenth embodiment has the same configuration andstructure as those of the semiconductor light emitting device of thefifth embodiment basically, and therefore the detailed descriptionthereof is omitted.

Modification examples of the semiconductor light emitting device of thethirteenth embodiment will be described below.

A modification example of the semiconductor light emitting device of thethirteenth embodiment shown in FIG. 11B corresponds to the semiconductorlight emitting device according to the ((I)-5-A-2)-th configuration ofthe present invention. Specifically, in this semiconductor lightemitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity (specifically, Si).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9B shown below. Table 9B isgiven the same notes as (Note 1) and (Note 2) of Table 9A (this appliesalso to Tables 9C to 9J to be described later).

TABLE 9B (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Thirdcompound semiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

A modification example of the semiconductor light emitting device of thethirteenth embodiment shown in FIGS. 12A and 12B corresponds to thesemiconductor light emitting device according to the ((I)-5-a)-thconfiguration of the present invention. In this semiconductor lightemitting device, the substitution site of the impurity in the firstcompound semiconductor layer, the substitution site of the impurity inthe second compound semiconductor layer, the substitution site of theimpurity in the fourth compound semiconductor layer, and thesubstitution site of the impurity in the third compound semiconductorlayer are the site occupied by a group V atom.

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.12A corresponds to the semiconductor light emitting device according tothe ((I)-5-a-1)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9C shown below.

TABLE 9C (Configuration of light emitting part) Second compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Second compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C Active layer [Activelayer-A] First compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Burying layer p-Al_(0.47)Ga_(0.53)As: Zn Thirdcompound semiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.12B corresponds to the semiconductor light emitting device according tothe ((I)-5-a-2)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity (specifically, Se).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9D shown below.

TABLE 9D (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C(Current block layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Thirdcompound semiconductor layer p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

A modification example of the semiconductor light emitting device of thethirteenth embodiment whose conceptual diagrams are shown in FIGS. 13Aand 13B corresponds to the semiconductor light emitting device accordingto the ((I)-5-B)-th configuration of the present invention. In thissemiconductor light emitting device,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer, and

the impurity for causing the 1B-th compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the 1B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 1A-th compoundsemiconductor layer for causing the 1A-th compound semiconductor layerto have the first conductivity type, and does not compete with thesubstitution site of the impurity in the second compound semiconductorlayer for causing the second compound semiconductor layer to have thesecond conductivity type. The impurity for causing the 1A-th compoundsemiconductor layer to have the first conductivity type is such that thesubstitution site of the impurity in the 1A-th compound semiconductorlayer competes with the substitution site of the impurity in the fourthcompound semiconductor layer for causing the fourth compoundsemiconductor layer to have the second conductivity type. Specifically,the substitution site of the impurity in the 1A-th compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 1B-th compound semiconductor layer is the site occupied by a group Vatom.

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.13A corresponds to the semiconductor light emitting device according tothe ((I)-5-B-1)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity (specifically, Si),

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity(specifically, Se),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity (specifically, Zn).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9E shown below.

TABLE 9E (Configuration of light emitting part) Second compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Activelayer-A] 1B-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se1A-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Currentblock layer) Burying layer p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer p-GaAs: Zn (or C)

A modification example of the semiconductor light emitting device of thethirteenth embodiment whose conceptual diagrams are shown in FIG. 13Bcorresponds to the semiconductor light emitting device according to the((I)-5-B-2)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity (specifically, Si).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9F shown below.

TABLE 9F (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn (Currentblock layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the thirteenthembodiment whose conceptual diagrams are shown in FIGS. 13A and 13B areshown in FIGS. 14A and 14B. In these further-modified examples,

a sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the sixth compound semiconductor layer competes with thesubstitution site of the impurity in the 1A-th compound semiconductorlayer for causing the 1A-th compound semiconductor layer to have thefirst conductivity type (specifically, a group IV impurity, Si, in FIG.14A, and a group II impurity, Zn, in FIG. 14B), and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer. The bypass channel iscomposed of the first compound semiconductor layer (the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer), thesixth compound semiconductor layer, the fourth compound semiconductorlayer, the third compound semiconductor layer, and the second compoundsemiconductor layer. The pn junction interfaces are formed of thefollowing three interfaces: the interface between the sixth compoundsemiconductor layer and the fourth compound semiconductor layer; theinterface between the fourth compound semiconductor layer and the thirdcompound semiconductor layer; and the interface between the thirdcompound semiconductor layer and the side surface of the second compoundsemiconductor layer.

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIGS.15A and 15B corresponds to the semiconductor light emitting deviceaccording to the ((I)-5-b)-th configuration of the present invention. Inthis semiconductor light emitting device, the substitution site of theimpurity in the 1A-th compound semiconductor layer, the substitutionsite of the impurity in the second compound semiconductor layer, thesubstitution site of the impurity in the fourth compound semiconductorlayer, and the substitution site of the impurity in the third compoundsemiconductor layer are the site occupied by a group V atom. Thesubstitution site of the impurity in the 1B-th compound semiconductorlayer is the site occupied by a group III atom. The substitution site ofthe impurity in the first burying layer is the site occupied by a groupV atom, and the substitution site of the impurity in the second buryinglayer is the site occupied by a group III atom.

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.15A corresponds to the semiconductor light emitting device according tothe ((I)-5-b-1)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity(specifically, Si),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9G shown below.

TABLE 9G (Configuration of light emitting part) Second compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Second compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C Active layer [Activelayer-A] 1B-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Si1A-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se (Currentblock layer) Burying layer p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.15B correspond to the semiconductor light emitting device according tothe ((I)-5-b-2)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity(specifically, Zn),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity (specifically, Se).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9H shown below.

TABLE 9H (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the thirteenthembodiment whose conceptual diagrams are shown in FIGS. 15A and 15B areshown in FIGS. 16A and 16B. Also in these further-modified examples,

the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the sixth compound semiconductor layer competes with thesubstitution site of the impurity in the 1A-th compound semiconductorlayer for causing the 1A-th compound semiconductor layer to have thefirst conductivity type (specifically, a group VI impurity, Se, in FIG.16A, and carbon (C) in FIG. 16B), and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer. The bypass channel iscomposed of the first compound semiconductor layer (the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer), thesixth compound semiconductor layer, the fourth compound semiconductorlayer, the third compound semiconductor layer, and the second compoundsemiconductor layer. The pn junction interfaces are formed of thefollowing three interfaces: the interface between the sixth compoundsemiconductor layer and the fourth compound semiconductor layer; theinterface between the fourth compound semiconductor layer and the thirdcompound semiconductor layer; and the interface between the thirdcompound semiconductor layer and the side surface of the second compoundsemiconductor layer.

A modification example of the semiconductor light emitting device of thethirteenth embodiment shown in FIGS. 17A and 17B is the semiconductorlight emitting device according to the ((I)-5-C)-th configuration of thepresent invention. In this semiconductor light emitting device,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer, and

the impurity for causing the 2B-th compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the 2B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 2A-th compoundsemiconductor layer for causing the 2A-th compound semiconductor layerto have the second conductivity type, and does not compete with thesubstitution site of the impurity in the first compound semiconductorlayer for causing the first compound semiconductor layer to have thefirst conductivity type. The impurity for causing the 2A-th compoundsemiconductor layer to have the second conductivity type is such thatthe substitution site of the impurity in the 2A-th compoundsemiconductor layer competes with the substitution site of the impurityin the third compound semiconductor layer for causing the third compoundsemiconductor layer to have the first conductivity type. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the 2A-thcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 2B-th compound semiconductor layer is the site occupied by a group Vatom.

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.17A correspond to the semiconductor light emitting device according tothe ((I)-5-C-1)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity (specifically, Si),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9I shown below.

TABLE 9I (Configuration of light emitting part) 2B-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C Active layer [Activelayer-A] First compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Si(Current block layer) Burying layer p-Al_(0.47)Ga_(0.53)As: Zn Thirdcompound semiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.17B correspond to the semiconductor light emitting device according tothe ((I)-5-C-2)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity (specifically, Si),

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity(specifically, Se).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9J shown below.

TABLE 9J (Configuration of light emitting part) 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Thirdcompound semiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the thirteenthembodiment whose conceptual diagrams are shown in FIGS. 17A and 17B areshown in FIGS. 18A and 18B. In these further-modified examples,

a fifth compound semiconductor layer of the second conductivity type isprovided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fifth compound semiconductor layer competes with thesubstitution site of the impurity in the 2A-th compound semiconductorlayer for causing the 2A-th compound semiconductor layer to have thesecond conductivity type (specifically, a group II impurity, Zn, in FIG.18A, and a group IV impurity, Si, in FIG. 18B), and

the fourth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer and the fifth compoundsemiconductor layer is in contact with the side surface of the secondcompound semiconductor layer (at least a part of the side surface of the2A-th compound semiconductor layer and all of the side surface of the2B-th compound semiconductor layer). The bypass channel is composed ofthe first compound semiconductor layer, the fourth compoundsemiconductor layer, the third compound semiconductor layer, the fifthcompound semiconductor layer, and the second compound semiconductorlayer (the 2A-th compound semiconductor layer and the 2B-th compoundsemiconductor layer). The pn junction interfaces are formed of thefollowing three interfaces: the interface between the side surface ofthe first compound semiconductor layer and the fourth compoundsemiconductor layer; the interface between the fourth compoundsemiconductor layer and the third compound semiconductor layer; and theinterface between the third compound semiconductor layer and the fifthcompound semiconductor layer.

A modification example of the semiconductor light emitting device of thethirteenth embodiment shown in FIGS. 19A and 19B as a conceptual diagramis the semiconductor light emitting device according to the ((I)-5-c)-thconfiguration of the present invention. In this semiconductor lightemitting device, the substitution site of the impurity in the firstcompound semiconductor layer, the substitution site of the impurity inthe 2A-th compound semiconductor layer, the substitution site of theimpurity in the fourth compound semiconductor layer, and thesubstitution site of the impurity in the third compound semiconductorlayer are the site occupied by a group V atom. The substitution site ofthe impurity in the 2B-th compound semiconductor layer is the siteoccupied by a group III atom.

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.19A correspond to the semiconductor light emitting device according tothe ((I)-5-c-1)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C),

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity(specifically, Zn).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9K shown below.

TABLE 9K (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] Firstcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se (Current blocklayer) Burying layer p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe thirteenth embodiment whose conceptual diagrams are shown in FIG.19B correspond to the semiconductor light emitting device according tothe ((I)-5-c-2)-th configuration of the present invention. In thissemiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity(specifically, Si).

More specifically, in this modification example of the semiconductorlight emitting device of the thirteenth embodiment, the respectivelayers have the configuration shown in Table 9L shown below.

TABLE 9L (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C(Current block layer) Burying layer n-Al_(0.47)Ga_(0.53)As: Se Thirdcompound semiconductor layer p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the thirteenthembodiment whose conceptual diagrams are shown in FIGS. 19A and 19B areshown in FIGS. 20A and 20B. Also in these further-modified examples,

the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fifth compound semiconductor layer competes with thesubstitution site of the impurity in the 2A-th compound semiconductorlayer for causing the 2A-th compound semiconductor layer to have thesecond conductivity type (specifically, carbon in FIG. 20A, and a groupVI impurity, Se, in FIG. 20B), and

the fourth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer and the fifth compoundsemiconductor layer is in contact with the side surface of the secondcompound semiconductor layer (at least a part of the side surface of the2A-th compound semiconductor layer and all of the side surface of the2B-th compound semiconductor layer). The bypass channel is composed ofthe first compound semiconductor layer, the fourth compoundsemiconductor layer, the third compound semiconductor layer, the fifthcompound semiconductor layer, and the second compound semiconductorlayer (the 2A-th compound semiconductor layer and the 2B-th compoundsemiconductor layer). The pn junction interfaces are formed of thefollowing three interfaces: the interface between the side surface ofthe first compound semiconductor layer and the fourth compoundsemiconductor layer; the interface between the fourth compoundsemiconductor layer and the third compound semiconductor layer; and theinterface between the third compound semiconductor layer and the fifthcompound semiconductor layer.

An impurity diffusion barrier layer may be provided in the current blocklayer. Specifically, in the fourth compound semiconductor layer that isincluded in the current block layer and has the second conductivitytype, at least one impurity diffusion barrier layer having the secondconductivity type (e.g. a seventh compound semiconductor layer) isprovided. Furthermore, impurities are so selected that the substitutionsite of the impurity in the fourth compound semiconductor layer isdifferent from that of the impurity in the impurity diffusion barrierlayer (e.g. the seventh compound semiconductor layer if the number ofimpurity diffusion barrier layers is one). More specifically, e.g. inthe structure shown in FIG. 13A or FIG. 14A, or in the structure shownin FIGS. 33A and 33B or FIGS. 34A and 34B, a configuration can beemployed in which the impurity in the fourth compound semiconductorlayer is zinc (Zn) and the impurity in the impurity diffusion barrierlayer (the seventh compound semiconductor layer) of the secondconductivity type provided in the fourth compound semiconductor layer iscarbon (C). That is, the configuration including the following layerscan be employed.

n-type third compound semiconductor layer (impurity: Si)p-type fourth compound semiconductor layer (impurity: Zn)p-type seventh compound semiconductor layer (impurity: C)p-type fourth compound semiconductor layer (impurity: Zn)In addition, e.g. in the structure shown in FIG. 13B or FIG. 14B, or inthe structure shown in FIGS. 35A and 35B or FIGS. 36A and 36B describedlater, a configuration can be employed in which the impurity in thefourth compound semiconductor layer is silicon (Si) and the impurity inthe impurity diffusion barrier layer (the seventh compound semiconductorlayer) of the second conductivity type provided in the fourth compoundsemiconductor layer is selenium (Se). That is, the configurationincluding the following layers can be employed.p-type third compound semiconductor layer (impurity: Zn)n-type fourth compound semiconductor layer (impurity: Si)n-type seventh compound semiconductor layer (impurity: Se)n-type fourth compound semiconductor layer (impurity: Si)In such a configuration, if a group VI impurity (Se) or carbon (C)diffuses from the 1B-th compound semiconductor layer into the currentblock layer (Zn-doped layer or Si-doped layer) for example, thisdiffused impurity can not diffuse in the seventh compound semiconductorlayer including the impurity (carbon or selenium) whose substitutionsite competes with the substitution site of this diffused impurity.Thus, the current block layer having high reliability can be formed.

Similarly, in the third compound semiconductor layer that is included inthe current block layer and has the first conductivity type, at leastone impurity diffusion barrier layer having the first conductivity type(e.g. an eighth compound semiconductor layer) is provided. Furthermore,impurities are so selected that the substitution site of the impurity inthe third compound semiconductor layer is different from that of theimpurity in the impurity diffusion barrier layer (e.g. the eighthcompound semiconductor layer if the number of impurity diffusion barrierlayers is one). For example, in the structure shown in FIG. 17A or FIG.18A, or in the structure shown in FIGS. 41A and 41B or FIGS. 42A and 42Bdescribed later, a configuration can be employed in which the impurityin the third compound semiconductor layer is silicon (Si) and theimpurity in the impurity diffusion barrier layer (the eighth compoundsemiconductor layer) of the first conductivity type provided in thethird compound semiconductor layer is selenium (Se). That is, theconfiguration including the following layers can be employed.

n-type third compound semiconductor layer (impurity: Si)n-type eighth compound semiconductor layer (impurity: Se)n-type third compound semiconductor layer (impurity: Si)p-type fourth compound semiconductor layer (impurity: Zn)In addition, in the structure shown in FIG. 17B or FIG. 18B, or in thestructure shown in FIGS. 43A and 43B or FIGS. 44A and 44B describedlater, a configuration can be employed in which the impurity in thethird compound semiconductor layer is zinc (Zn) and the impurity in theimpurity diffusion barrier layer (the eighth compound semiconductorlayer) of the first conductivity type provided in the third compoundsemiconductor layer is carbon (C). That is, the configuration includingthe following layers can be employed.p-type third compound semiconductor layer (impurity: Zn)p-type eighth compound semiconductor layer (impurity: C)p-type third compound semiconductor layer (impurity: Zn)n-type fourth compound semiconductor layer (impurity: Si)Also in such a configuration, if carbon (C) or selenium (Se) diffusesfrom the 2B-th compound semiconductor layer into the current block layer(Si-doped layer or Zn-doped layer) for example, this diffused impuritycan not diffuse in the eighth compound semiconductor layer including theimpurity (group VI impurity, Se, or carbon) whose substitution sitecompetes with the substitution site of this diffused impurity. Thus, thecurrent block layer having high reliability can be formed.

The same feature can be employed also for other semiconductor lightemitting devices in which the first compound semiconductor layer iscomposed of the 1A-th compound semiconductor layer and the 1B-thcompound semiconductor layer and other semiconductor light emittingdevices in which the second compound semiconductor layer is composed ofthe 2A-th compound semiconductor layer and the 2B-th compoundsemiconductor layer.

The effect of the impurity diffusion barrier in the form in which theimpurity diffusion barrier layer (seventh compound semiconductor layeror eighth compound semiconductor layer) is provided is readily obtainedin the structures of FIGS. 14A and 14B, 16A and 16B, 18A and 18B, and20A and 20B, and FIGS. 34A and 34B, 36A and 36B, 38A and 38B, 40A and40B, 42A and 42B, 44A and 44B, 46A and 46B, and 48A and 48B describedlater in particular. Therefore, the examples are cited as above in whichone seventh compound semiconductor layer or one eighth compoundsemiconductor layer as the impurity diffusion barrier layer is providedin the compound semiconductor layer (fourth compound semiconductor layeror third compound semiconductor layer) having the same conductivity typeas that of the seventh compound semiconductor layer or the eighthcompound semiconductor layer. However, the number of impurity diffusionbarrier layers for the purpose of impurity diffusion barrier may be twoor larger as long as the impurity diffusion barrier layers are formed ofcompound semiconductor layers having the same substitution site of theimpurity as that of the impurity that diffuses into the current blocklayer from the first compound semiconductor layer (or the 1B-th compoundsemiconductor layer) or the second compound semiconductor layer (or the2B-th compound semiconductor layer). Furthermore, the position of theimpurity diffusion barrier layer is not limited to the inside of acompound semiconductor layer having the same conductivity type as thatof the impurity diffusion barrier layer, but one or more impuritydiffusion barrier layers may be provided in a compound semiconductorlayer having the different conductivity type.

In addition, the current block layer may have a multilayer structure.Specifically, e.g. in the structure shown in FIG. 14A, or in thestructure shown in FIGS. 34A and 34B described later, instead of usingthe current block layer having the multilayer structure of the n-typethird compound semiconductor layer/the p-type fourth compoundsemiconductor layer/the n-type sixth compound semiconductor layer, thecurrent block layer having the following five-layer structure may beused without changing the thickness of the entire current block layer.

(1) n-type third compound semiconductor layer (impurity: Si)(2) p-type compound semiconductor layer (impurity: Zn)(3) n-type compound semiconductor layer (impurity: Si)(4) p-type fourth compound semiconductor layer (impurity: Zn)(5) n-type sixth compound semiconductor layer (impurity: Si)

Alternatively, the current block layer having the following seven-layerstructure may be used.

(1) n-type third compound semiconductor layer (impurity: Si)(2) p-type compound semiconductor layer (impurity: Zn)(3) n-type compound semiconductor layer (impurity: Si)(4) p-type compound semiconductor layer (impurity: Zn)(5) n-type compound semiconductor layer (impurity: Si)(6) p-type fourth compound semiconductor layer (impurity: Zn)(7) n-type sixth compound semiconductor layer (impurity: Si)

Alternatively, the current block layer having the following nine-layerstructure may be used.

(1) n-type third compound semiconductor layer (impurity: Si)(2) p-type compound semiconductor layer (impurity: Zn)(3) n-type compound semiconductor layer (impurity: Si)(4) p-type compound semiconductor layer (impurity: Zn)(5) n-type compound semiconductor layer (impurity: Si)(6) p-type compound semiconductor layer (impurity: Zn)(7) n-type compound semiconductor layer (impurity: Si)(8) p-type fourth compound semiconductor layer (impurity: Zn)(9) n-type sixth compound semiconductor layer (impurity: Si)

Alternatively, the current block layer having the following eleven-layerstructure may be used.

(1) n-type third compound semiconductor layer (impurity: Si)(2) p-type compound semiconductor layer (impurity: Zn)(3) n-type compound semiconductor layer (impurity: Si)(4) p-type compound semiconductor layer (impurity: Zn)(5) n-type compound semiconductor layer (impurity: Si)(6) p-type compound semiconductor layer (impurity: Zn)(7) n-type compound semiconductor layer (impurity: Si)(8) p-type compound semiconductor layer (impurity: Zn)(9) n-type compound semiconductor layer (impurity: Si)(10) p-type fourth compound semiconductor layer (impurity: Zn)(11) n-type sixth compound semiconductor layer (impurity: Si)

Similarly, in the structure shown in FIG. 16A, or in the structure shownin FIGS. 38A and 38B described later, instead of using the current blocklayer having the multilayer structure of the n-type third compoundsemiconductor layer/the p-type fourth compound semiconductor layer/then-type sixth compound semiconductor layer, the current block layerhaving the following five-layer structure may be used without changingthe thickness of the entire current block layer.

(1) n-type third compound semiconductor layer (impurity: Se)(2) p-type compound semiconductor layer (impurity: C)(3) n-type compound semiconductor layer (impurity: Se)(4) p-type fourth compound semiconductor layer (impurity: C)(5) n-type sixth compound semiconductor layer (impurity: Se)

Alternatively, the current block layer having the following seven-layerstructure may be used.

(1) n-type third compound semiconductor layer (impurity: Se)(2) p-type compound semiconductor layer (impurity: C)(3) n-type compound semiconductor layer (impurity: Se)(4) p-type compound semiconductor layer (impurity: C)(5) n-type compound semiconductor layer (impurity: Se)(6) p-type fourth compound semiconductor layer (impurity: C)(7) n-type sixth compound semiconductor layer (impurity: Se)

Alternatively, the current block layer having the following nine-layerstructure may be used.

(1) n-type third compound semiconductor layer (impurity: Se)(2) p-type compound semiconductor layer (impurity: C)(3) n-type compound semiconductor layer (impurity: Se)(4) p-type compound semiconductor layer (impurity: C)(5) n-type compound semiconductor layer (impurity: Se)(6) p-type compound semiconductor layer (impurity: C)(7) n-type compound semiconductor layer (impurity: Se)(8) p-type fourth compound semiconductor layer (impurity: C)(9) n-type sixth compound semiconductor layer (impurity: Se)

Alternatively, the current block layer having the following eleven-layerstructure may be used.

(1) n-type third compound semiconductor layer (impurity: Se)(2) p-type compound semiconductor layer (impurity: C)(3) n-type compound semiconductor layer (impurity: Se)(4) p-type compound semiconductor layer (impurity: C)(5) n-type compound semiconductor layer (impurity: Se)(6) p-type compound semiconductor layer (impurity: C)(7) n-type compound semiconductor layer (impurity: Se)(8) p-type compound semiconductor layer (impurity: C)(9) n-type compound semiconductor layer (impurity: Se)(10) p-type fourth compound semiconductor layer (impurity: C)(11) n-type sixth compound semiconductor layer (impurity: Se)

Furthermore, in the structure shown in FIG. 14B, or in the structureshown in FIGS. 36A and 36B described later, instead of using the currentblock layer having the multilayer structure of the p-type third compoundsemiconductor layer/the n-type fourth compound semiconductor layer/thep-type sixth compound semiconductor layer, the current block layerhaving the following five-layer structure may be used without changingthe thickness of the entire current block layer.

(1) p-type third compound semiconductor layer (impurity: Zn)(2) n-type compound semiconductor layer (impurity: Si)(3) p-type compound semiconductor layer (impurity: Zn)(4) n-type fourth compound semiconductor layer (impurity: Si)(5) p-type sixth compound semiconductor layer (impurity: Zn)

Alternatively, the current block layer having the following seven-layerstructure may be used.

(1) p-type third compound semiconductor layer (impurity: Zn)(2) n-type compound semiconductor layer (impurity: Si)(3) p-type compound semiconductor layer (impurity: Zn)(4) n-type compound semiconductor layer (impurity: Si)(5) p-type compound semiconductor layer (impurity: Zn)(6) n-type fourth compound semiconductor layer (impurity: Si)(7) p-type sixth compound semiconductor layer (impurity: Zn)

Alternatively, the current block layer having the following nine-layerstructure may be used.

(1) p-type third compound semiconductor layer (impurity: Zn)(2) n-type compound semiconductor layer (impurity: Si)(3) p-type compound semiconductor layer (impurity: Zn)(4) n-type compound semiconductor layer (impurity: Si)(5) p-type compound semiconductor layer (impurity: Zn)(6) n-type compound semiconductor layer (impurity: Si)(7) p-type compound semiconductor layer (impurity: Zn)(8) n-type fourth compound semiconductor layer (impurity: Si)(9) p-type sixth compound semiconductor layer (impurity: Zn)

Alternatively, the current block layer having the following eleven-layerstructure may be used.

(1) p-type third compound semiconductor layer (impurity: Zn)(2) n-type compound semiconductor layer (impurity: Si)(3) p-type compound semiconductor layer (impurity: Zn)(4) n-type compound semiconductor layer (impurity: Si)(5) p-type compound semiconductor layer (impurity: Zn)(6) n-type compound semiconductor layer (impurity: Si)(7) p-type compound semiconductor layer (impurity: Zn)(8) n-type compound semiconductor layer (impurity: Si)(9) p-type compound semiconductor layer (impurity: Zn)(10) n-type fourth compound semiconductor layer (impurity: Si)(11) p-type sixth compound semiconductor layer (impurity: Zn)

Similarly, in the structure shown in FIG. 16B, or in the structure shownin FIGS. 40A and 40B described later, instead of using the current blocklayer having the multilayer structure of the p-type third compoundsemiconductor layer/the n-type fourth compound semiconductor layer/thep-type sixth compound semiconductor layer, the current block layerhaving the following five-layer structure may be used without changingthe thickness of the entire current block layer.

(1) p-type third compound semiconductor layer (impurity: C)(2) n-type compound semiconductor layer (impurity: Se)(3) p-type compound semiconductor layer (impurity: C)(4) n-type fourth compound semiconductor layer (impurity: Se)(5) p-type sixth compound semiconductor layer (impurity: C)

Alternatively, the current block layer having the following seven-layerstructure may be used.

(1) p-type third compound semiconductor layer (impurity: C)(2) n-type compound semiconductor layer (impurity: Se)(3) p-type compound semiconductor layer (impurity: C)(4) n-type compound semiconductor layer (impurity: Se)(5) p-type compound semiconductor layer (impurity: C)(6) n-type fourth compound semiconductor layer (impurity: Se)(7) p-type sixth compound semiconductor layer (impurity: C)

Alternatively, the current block layer having the following nine-layerstructure may be used.

(1) p-type third compound semiconductor layer (impurity: C)(2) n-type compound semiconductor layer (impurity: Se)(3) p-type compound semiconductor layer (impurity: C)(4) n-type compound semiconductor layer (impurity: Se)(5) p-type compound semiconductor layer (impurity: C)(6) n-type compound semiconductor layer (impurity: Se)(7) p-type compound semiconductor layer (impurity: C)(8) n-type fourth compound semiconductor layer (impurity: Se)(9) p-type sixth compound semiconductor layer (impurity: C)

Alternatively, the current block layer having the following eleven-layerstructure may be used.

(1) p-type third compound semiconductor layer (impurity: C)(2) n-type compound semiconductor layer (impurity: Se)(3) p-type compound semiconductor layer (impurity: C)(4) n-type compound semiconductor layer (impurity: Se)(5) p-type compound semiconductor layer (impurity: C)(6) n-type compound semiconductor layer (impurity: Se)(7) p-type compound semiconductor layer (impurity: C)(8) n-type compound semiconductor layer (impurity: Se)(9) p-type compound semiconductor layer (impurity: C)(10) n-type fourth compound semiconductor layer (impurity: Se)(11) p-type sixth compound semiconductor layer (impurity: C)

By thus employing the current block layer having a multilayer structurewithout increasing the total thickness of the current block layer, it ispossible to select the design in which the thicknesses of the respectivecompound semiconductor layers included in the current block layer (atleast one compound semiconductor layer of all the above-describedcompound semiconductor layers from the third compound semiconductorlayer to the sixth compound semiconductor layer, or at least onecompound semiconductor layer of all of the compound semiconductor layersfrom the fifth compound semiconductor layer to the fourth compoundsemiconductor layer in the structures of FIGS. 18A and 18B and FIGS. 20Aand 20B, or in the structures of FIGS. 42A and 42B, FIGS. 44A and 44B,FIGS. 46A and 46B, and FIGS. 48A and 48B described later similarly tothe above description) are set small optionally. Thus, the contact areaof the surface in contact with the side surface of the light emittingpart per one layer included in the current block layer can be decreased.If the thicknesses of the respective compound semiconductor layersincluded in the current block layer are so adjusted that the contactarea of the contact surface is further decreased, it becomes possible toavoid the state in which the entire side surface of the active layer (orwell layer) is covered by the contact surface of only one layer includedin the current block layer, which allows further-ensured prevention ofthe phenomenon that a current leakage path from the bypass channel isformed.

In the thirteenth embodiment or thirteenth embodiment described later,it is also possible to employ the configuration that includes both thefirst compound semiconductor layer composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer and thesecond compound semiconductor layer composed of the 2A-th compoundsemiconductor layer and the 2B-th compound semiconductor layer.

Fourteenth Embodiment

A fourteenth embodiment of the present invention relates to thesemiconductor light emitting device according to ((II)-1)-thconfiguration (specifically, the ((II)-1-A)-th configuration), the((II)-2-A)-th configuration, and the ((II)-4-A)-th configuration of thepresent invention.

Conceptual diagrams of the semiconductor light emitting device of thefourteenth embodiment are shown in FIGS. 21A and 21B. Schematic partialsectional views of the semiconductor light emitting device are shown inFIGS. 49 and 50. Enlarged schematic partial sectional views of thesemiconductor light emitting device are shown in FIGS. 51A to 51C. FIG.21A is a conceptual diagram of the end parts of the semiconductor lightemitting device. FIG. 21B is a conceptual diagram of the center part ofthe semiconductor light emitting device. FIG. 49 is a schematic partialsectional view of the center part of the semiconductor light emittingdevice. FIG. 50 is a schematic partial sectional view of the end partsof the semiconductor light emitting device. FIG. 51A is an enlargedschematic partial sectional view of a current block layer and theperiphery thereof. FIGS. 51B and 51C are enlarged schematic partialsectional views of a light emitting part and the periphery thereof atthe end parts of the semiconductor light emitting device. In thedrawings, the thicknesses of some compound semiconductor layers in thesectional structure of the semiconductor light emitting device at thecenter part thereof shown in FIG. 49 look different from those of thesame compound semiconductor layers in the sectional structure of thesemiconductor light emitting device at both the end parts thereof shownin FIG. 50. However, the same layer actually has the same thickness.

The semiconductor light emitting device of the fourteenth embodimentfurther includes a burying layer 31 formed over the current block layer40 and the light emitting part 20. The active layer 23 is stacked abovethe underlying layer 111 having the planar shape (so-called mesastructure) as with the projection part 211 schematically shown in FIG.60B. Thus, the active layer 23 has a strip planar shape in which thewidth of the center part is smaller than that of both the end parts.That is, the semiconductor light emitting devices of the fourteenthembodiment and the fifteenth to twenty-second embodiments to bedescribed later have a so-called flare-stripe structure.

The burying layer 31 of the second conductivity type is formed of amultilayer structure arising from sequential stacking of a first buryinglayer 31A and a second burying layer 31B. In the burying layer 31located above the current block layer 40, the impurity for causing thesecond burying layer 31B to have the second conductivity type is suchthat the substitution site of the impurity in the second burying layer31B does not compete with the substitution site of the impurity in thethird compound semiconductor layer 43 for causing the third compoundsemiconductor layer 43 to have the first conductivity type. Furthermore,in the burying layer 31 located above the current block layer 40, theimpurity for causing the first burying layer 31A to have the secondconductivity type is such that the substitution site of the impurity inthe first burying layer 31A competes with the substitution site of theimpurity in the third compound semiconductor layer 43 for causing thethird compound semiconductor layer 43 to have the first conductivitytype. In addition, in the burying layer 31 located above the currentblock layer 40, the impurity for causing the first burying layer 31A tohave the second conductivity type is such that the substitution site ofthe impurity in the first burying layer 31A competes with thesubstitution site of the impurity in the fourth compound semiconductorlayer 44 for causing the fourth compound semiconductor layer 44 to havethe second conductivity type. These features apply also to the fifteenthto twenty-second embodiments to be described later.

In the example shown in FIGS. 49 and 50, as explained in the fifthembodiment, the third compound semiconductor layer 43 is formed on thefourth compound semiconductor layer 44. Alternatively, as explained inthe fifth embodiment, the positional relationship between the thirdcompound semiconductor layer 43 (n-type) and the fourth compoundsemiconductor layer 44 (p-type) may be reversed.

Specifically, when the semiconductor light emitting device of thefourteenth embodiment is represented based on the ((II)-1-A)-thconfiguration of the present invention, in the semiconductor lightemitting device of the fourteenth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the third compound semiconductor layer43, the fourth compound semiconductor layer 44, the first burying layer31A, and the second burying layer 31B are composed of a III-V compoundsemiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group IIIatom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupIII atom,

the substitution site of the impurity in the first burying layer 31A isthe site occupied by a group III atom, and

the substitution site of the impurity in the second burying layer 31B isthe site occupied by a group V atom.

Furthermore, when the semiconductor light emitting device of thefourteenth embodiment is represented based on the ((II)-2-A)-thconfiguration of the present invention, in the semiconductor lightemitting device of the fourteenth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the third compound semiconductor layer43, the fourth compound semiconductor layer 44, the first burying layer31A, and the second burying layer 31B are composed of a III-V compoundsemiconductor,

the impurity for causing the first compound semiconductor layer 21 to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the third compound semiconductor layer 43 to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the first burying layer 31A to be the p-type asthe second conductivity type is a group II impurity, and

the impurity for causing the second burying layer 31B to be the p-typeas the second conductivity type is carbon (C).

In addition, when the semiconductor light emitting device of thefourteenth embodiment is represented based on the ((II)-4-A)-thconfiguration of the present invention, in the semiconductor lightemitting device of the fourteenth embodiment, the impurity for causingthe first compound semiconductor layer 21 to have the first conductivitytype (n-type) is different from the impurity for causing the thirdcompound semiconductor layer 43 to have the first conductivity type(n-type).

Specifically, in the semiconductor light emitting device of thefourteenth embodiment, the respective layers have the configurationshown in Table 11A or Table 11B shown below. The compound semiconductorsof the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, and the current block layer 40 havewider band gaps, i.e., lower refractive indexes, compared with thecompound semiconductors of the active layer 23. In the example shown inTable 11A, the third compound semiconductor layer 43 is stacked on thefourth compound semiconductor layer 44. In the example shown in Table11B, the fourth compound semiconductor layer 44 is stacked on the thirdcompound semiconductor layer 43.

TABLE 11A (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Second burying layer 31B p-Al_(0.47)Ga_(0.53)As: CFirst burying layer 31A p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer 30p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer 43 and the firstburying layer 31A (the partial portion of the first burying layer 31A inthe vicinity of the interface with the third compound semiconductorlayer 43 corresponds to this fifth compound semiconductor layer).

TABLE 11B (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Second burying layer 31B p-Al_(0.47)Ga_(0.53)As: CFirst burying layer 31A p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Si Adjustment layer 30p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The first burying layer 31Ais formed subsequently to the fourth compound semiconductor layer 44 ina continuous manner, and a boundary does not exist between the firstburying layer 31A and the fourth compound semiconductor layer 44substantially.

In the manufacturing process of the semiconductor light emitting deviceof the fourteenth embodiment, at the timing when the formation of thelight emitting part 20 is completed, the sectional shape of the lightemitting part 20 obtained when the center part of the light emittingpart 20 is cut along a virtual plane perpendicular to the axis line ofthe light emitting part 20 is a triangle. At this time, the sectionalshape of the light emitting part 20 obtained when the end part of thelight emitting part 20 is cut along a virtual plane perpendicular to theaxis line of the light emitting part 20 is a trapezoid. Therefore, inthe formation of the current block layer 40 (the fourth compoundsemiconductor layer 44 and the third compound semiconductor layer 43),the current block layer 40 is formed only on the side surfaces of thelight emitting part 20 at the center part of the light emitting part 20.At this time, at the end parts of the light emitting part 20, inaddition to the formation of the current block layer 40 on the sidesurfaces of the light emitting part 20, a layer (deposited layer 40″)having the same multilayer structure as that of the current block layer40 is formed above the top surface of the light emitting part 20 (seeFIG. 51B). The fourth compound semiconductor layer included in thedeposited layer 40″ at the timing when the deposited layer 40″ is formedwill be referred to as a deposited layer 44′ of the fourth compoundsemiconductor layer, and the third compound semiconductor layer includedin the deposited layer 40″ at the same timing will be referred to as adeposited layer 43″ of the third compound semiconductor layer. Betweenthe deposited layer 40″ and the top surface of the multilayer structureof the light emitting part 20, a compound semiconductor layer 30′ havingthe same configuration as that of the adjustment layer 30 is formed.

Subsequently to the formation of the current block layer 40, the firstburying layer 31A is so formed as to cover the side surfaces of thelight emitting part 20 and the side surfaces of at least one layer ofthe deposited layer 40″ stacked above the light emitting part 20, atboth the end parts in particular. Subsequently, at the timing of thecompletion of the covering of at least the side surfaces of the lightemitting part 20 and the side surfaces of the compound semiconductorlayer 30′ by the first burying layer 31A, the formation of the secondburying layer 31B is started, so that the entire surface is covered bythe second burying layer 31B. At this time, the impurity for causing thesecond burying layer 31B to have the second conductivity type is suchthat the substitution site of the impurity in the second burying layer31B (the site occupied by a group V atom, in the fourteenth embodiment)does not compete with the substitution site of the impurity in the thirdcompound semiconductor layer (the site occupied by a group III atom, inthe fourteenth embodiment) for causing the third compound semiconductorlayer 43 to have the first conductivity type (see Table 11A or Table11B). Therefore, e.g. the impurity for causing the second burying layer31B that is deposited to a large thickness so that the apex may befinally covered to have the second conductivity type diffuses into thedeposited layer 43″ of the third compound semiconductor layer, formedabove the top surface at both the end parts of the light emitting part20. This diffusion turns the deposited layer 43″ of the third compoundsemiconductor layer to a deposited layer 43′ of the third compoundsemiconductor layer, having the second conductivity type (see FIG. 51C).The deposited layer that has become such a state will be referred to asa deposited layer vestige 40′. Furthermore, the first burying layer andthe second burying layer formed above the deposited layer vestige 40′will be referred to as a first burying layer 31A′ and a second buryinglayer 31B,′ respectively. In FIGS. 21A, 22A, 23A, 24A, 25A, 26A, 27A,28A, 29A, 30A, 31A, 32A, 33A, 34A, 35A, 36A, 37A, 38A, 39A, 40A, 41A,42A, 43A, 44A, 45A, 46A, 47A and 48A, the deposited layer 43′ of thethird compound semiconductor layer is indicated as “3′-rd layer,” andthe deposited layer 44′ of the fourth compound semiconductor layer isindicated as “4′-th layer.” In particular, if a compound semiconductorlayer of the first conductivity type is included in the deposited layer40″, it is desirable that the burying layer 31 of the secondconductivity type whose impurity substitution site does not compete withthe impurity substitution site in this compound semiconductor layer ofthe first conductivity type included in the deposited layer 40″ be incontact with at least a part of the side surface of the deposited layer40″. This structure allows the impurity of the second conductivity typein the burying layer 31 (e.g. the burying layer 31B) to diffuse from theat least a part of the side surface of the deposited layer 40″. As aresult, it is possible to initially carry out conductivity typecompensation for the compound semiconductor layer of the firstconductivity type that is included in the deposited layer 40″ and causesthe current blocking, and thus turn this compound semiconductor layer ofthe first conductivity type to a layer of the second conductivity type.

The semiconductor light emitting device of the fourteenth embodiment canbe manufactured based on a method described below for example. That is,based on the similar steps of [Step-100] to [Step-110] in the firstembodiment, the underlying layer 111 having the planar shape shown inFIG. 60B is formed. In FIG. 60B, the underlying layer 111 is hatched forclearly showing it.

Subsequently, in the same manner as [Step-120] in the first embodiment,above the top surface of the underlying layer 111, the light emittingpart 20 is formed arising from sequential stacking of the first compoundsemiconductor layer 21 of the first conductivity type, an active layer23, and the second compound semiconductor layer 22 of the secondconductivity type, and, on an exposed major surface of the substrate 10,the multilayer structure is formed arising from sequential stacking ofthe first compound semiconductor layer 21 of the first conductivitytype, the active layer 23, and the second compound semiconductor layer22 of the second conductivity type. By properly selecting the width andthickness of the underlying layer 111 (projection surface) and properlyselecting the thicknesses of the buffer layer 12, the first compoundsemiconductor layer 21, the active layer 23, and the second compoundsemiconductor layers 22A and 22B, a multilayer structure of the lightemitting part 20 having a triangular sectional shape can be obtainedabove the center part of the underlying layer 111 (projection surface).At this time, at both the end parts of the underlying layer 111, amultilayer structure of the light emitting part 20 having a trapezoidalsectional shape can be obtained simultaneously. Thereafter, in theprocess of the continuation of the growth of the layers subsequent tothe second compound semiconductor layer 22, at the center part, the sidesurfaces of the triangle in the growth stop state are gradually covered,so that the apex of the triangle is also completely covered by thesecond burying layer finally. On the other hand, at both the end parts,the growth of the compound semiconductor layer continues on the topsurface ({100} plane) of the trapezoid in the process of thecontinuation of the growth of the layers subsequent to the secondcompound semiconductor layer 22. Thus, for example, a triangle (apex)having a larger sectional area compared with the triangle of the centerpart is eventually formed. Furthermore, the side surfaces of thistriangle are gradually covered, so that the apex is also completelycovered by the second burying layer finally.

Specifically, continuously with the formation of the second compoundsemiconductor layer 22B, the adjustment layer 30 is formed across theentire surface based on MOCVD. Subsequently, for example, the currentblock layer 40 formed of the multilayer structure composed of the fourthcompound semiconductor layer 44 and the third compound semiconductorlayer 43 is formed based on MOCVD. In this way, the sectional structureshown in FIG. 5 can be obtained at the center part of the underlyinglayer 111. At both the end parts of the underlying layer 111, thesectional structure shown in FIG. 52 can be obtained. The current blocklayer 40 is not grown on the {111}B plane. The current block layer 40 isso formed that the end surfaces of the current block layer 40 cover atleast the side surfaces of the active layer 23. Such configuration andstructure can be achieved by properly selecting the width of the topsurface of the underlying layer 111 and the height of the underlyinglayer 111 and by properly selecting the thickness of the adjustmentlayer 30. The configurations and structures of the third compoundsemiconductor layer 43 and the fourth compound semiconductor layer 44are as described above.

Subsequently, the first burying layer 31A, the second burying layer 31B,and the contact layer (cap layer) 32 are sequentially formed across theentire surface based on MOCVD. Specifically, if the MOCVD is continued,the first burying layer 31A composed of the compound semiconductorarising from the crystal growth from the exposed surface of thesubstrate 10 will, in time, completely cover the side surfaces of thelight emitting part 20 in the self growth stop state, and, at both theend parts, at least the side surfaces of one layer of the depositedlayer 40″ stacked above the light emitting part 20. In this state, thegrowth of the first burying layer 31A is stopped. Subsequently, thesecond burying layer 31B is grown, so that the entire surface iscompletely buried by the second burying layer 31B. In this way, thesectional structure shown in FIG. 53 can be obtained at the center partof the underlying layer 111. At both the end parts of the underlyinglayer 111, the sectional structure shown in FIG. 54 can be obtained.Thereafter, the second electrode 52 is formed on the contact layer 32based on the vacuum evaporation. Furthermore, the substrate 10 is lappedto a proper thickness from the backside thereof, and then the firstelectrode 51 is formed based on vacuum evaporation. In this way, thesectional structure shown in FIG. 49 can be obtained at the center partof the underlying layer 111. At both the end parts of the underlyinglayer 111, the sectional structure shown in FIG. 50 can be obtained.

Thereafter, the respective semiconductor light emitting devices areseparated from each other, so that the semiconductor light emittingdevices can be obtained. The semiconductor light emitting devices of thefifteenth to twenty-second embodiments to be described later can also bemanufactured based on a method similar to the above-described methodbasically.

In the burying layer 31 located above the current block layer 40, theimpurity for causing the first burying layer 31A to have the secondconductivity type is such that the substitution site of the impurity inthe first burying layer 31A competes with the substitution site of theimpurity in the fourth compound semiconductor layer 44 for causing thefourth compound semiconductor layer 44 to have the second conductivitytype. This feature allows ensured prevention of the diffusion of theimpurity in the first burying layer 31A into the fourth compoundsemiconductor layer 44. On the other hand, the impurity for causing thesecond burying layer 31B to have the second conductivity type is suchthat the substitution site of the impurity in the second burying layer31B does not compete with the substitution site of the impurity in thethird compound semiconductor layer 43 for causing the third compoundsemiconductor layer 43 to have the first conductivity type. Therefore,the impurity for causing the second burying layer 31B to have the secondconductivity type diffuses into the deposited layer 43″ of the thirdcompound semiconductor layer, having the first conductivity type, in thedeposited layer 40″ formed above the top surface at both the end partsof the light emitting part 20 at the same timing as that of the currentblock layer. This impurity diffusion turns the deposited layer 43″ ofthe third compound semiconductor layer to the deposited layer 43′ of thethird compound semiconductor layer, having the second conductivity type.As a result, all of the compound semiconductor layers located above thelight emitting part 20 at both the end parts of the light emitting part20 have the second conductivity type. Therefore, the deposited layerhaving the same multilayer structure as that of the current block layer40 does not exist above the top surface of the multilayer structure ofthe light emitting part 20, and the current injection path to the activelayer 23 is not limited to the {111}B side surface (contact surface).This allows ensured avoidance of the occurrence of a problem that theelectric resistance is increased and thus the heat generation and thecurrent consumption are increased, and hence a problem that the lightemission efficiency of the semiconductor light emitting device isdecreased. This basic principle applies also to the fifteenth totwenty-second embodiments to be described later.

Fifteenth Embodiment

The fifteenth embodiment is a modification of the fourteenth embodiment,and relates to the ((II)-1-B)-th configuration of the present inventionand the ((II)-2-B)-th configuration of the present invention.

Specifically, as shown in FIG. 22A as a conceptual diagram of the endparts of the light emitting part and FIG. 22B as a conceptual diagram ofthe center part of the light emitting part, when the semiconductor lightemitting device of the fifteenth embodiment is represented based on the((II)-1-B)-th configuration of the present invention, in thesemiconductor light emitting device of the fifteenth embodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, a fourth compoundsemiconductor layer, a first burying layer, and a second burying layerare composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom.

Furthermore, when the semiconductor light emitting device of thefifteenth embodiment is represented based on the ((II)-2-B)-thconfiguration of the present invention, in the semiconductor lightemitting device of the fifteenth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is carbon (C).

More specifically, in the semiconductor light emitting device of thefifteenth embodiment, the respective layers have the configuration shownin Table 12A or Table 12B shown below. In the example shown in Table12A, the third compound semiconductor layer is stacked on the fourthcompound semiconductor layer. In the example shown in Table 12B, thefourth compound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 12A (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] 1B-thcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 1A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Current block layer)Second burying layer p-Al_(0.47)Ga_(0.53)As: C First burying layerp-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Si Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer p-Al_(0.47)Ga_(0.53)As: Zn(Whole) Contact layer p-GaAs: Zn (or C) (Note 1) The adjustment layer isformed subsequently to the 2A-th compound semiconductor layer. (Note 2)The fourth compound semiconductor layer is formed subsequently to theadjustment layer in a continuous manner, and a boundary does not existbetween the fourth compound semiconductor layer and the adjustment layersubstantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: Zn isformed between the third compound semiconductor layer and the firstburying layer (the partial portion of the first burying layer in thevicinity of the interface with the third compound semiconductor layercorresponds to this fifth compound semiconductor layer).

TABLE 12B (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] 1B-thcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 1A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Current block layer)Second burying layer p-Al_(0.47)Ga_(0.53)As: C First burying layerp-Al_(0.47)Ga_(0.53)As: Zn Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Si Adjustment layer p-Al_(0.47)Ga_(0.53)As: Zn(Whole) Contact layer p-GaAs: Zn (or C) (Note 1) The adjustment layer isformed subsequently to the 2A-th compound semiconductor layer. (Note 2)The first burying layer is formed subsequently to the fourth compoundsemiconductor layer in a continuous manner, and a boundary does notexist between the first burying layer and the fourth compoundsemiconductor layer substantially.

Sixteenth Embodiment

The sixteenth embodiment is also a modification of the fourteenthembodiment, and relates to the ((II)-1-C)-th configuration of thepresent invention, the ((II)-2-C)-th configuration of the presentinvention, and the ((II)-4-A)-th configuration of the present invention.In the sixteenth embodiment and the seventeenth embodiment to bedescribed later, the conductivity types are reversed from those in thefourteenth embodiment. That is, in the sixteenth embodiment and theseventeenth embodiment to be described later, the first conductivitytype is the p-type and the second conductivity type is the n-type.

Specifically, a conceptual diagram of the light emitting part at the endparts is shown in FIG. 23A. A conceptual diagram of the light emittingpart at the center part is shown in FIG. 23B. Schematic partialsectional views are shown in FIGS. 55 and 56. Enlarged schematic partialsectional views are shown in FIGS. 57A to 57C. FIG. 55 is a schematicpartial sectional view of the center part of the semiconductor lightemitting device. FIG. 56 is a schematic partial sectional view of theend parts of the semiconductor light emitting device. FIG. 57A is anenlarged schematic partial sectional view of a current block layer andthe periphery thereof. FIGS. 57B and 57C are enlarged schematic partialsectional views of the light emitting part and the periphery thereof atthe end parts of the semiconductor light emitting device.

When the semiconductor light emitting device of the sixteenth embodimentis represented based on the ((II)-1-C)-th configuration of the presentinvention, in the semiconductor light emitting device of the sixteenthembodiment,

a first compound semiconductor layer 21, second compound semiconductorlayers 22A and 22B, a current block layer 40 (a third compoundsemiconductor layer 43 and a fourth compound semiconductor layer 44), afirst burying layer, and a second burying layer are composed of a III-Vcompound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupV atom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom.

Furthermore, when the semiconductor light emitting device of thesixteenth embodiment is represented based on the ((II)-2-C)-thconfiguration of the present invention, in the semiconductor lightemitting device of the sixteenth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the current block layer 40 (the thirdcompound semiconductor layer 43 and the fourth compound semiconductorlayer 44), the first burying layer, and the second burying layer arecomposed of a III-V compound semiconductor,

the impurity for causing the first compound semiconductor layer 21 to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the third compound semiconductor layer 43 to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group IV impurity.

Furthermore, when the semiconductor light emitting device of thesixteenth embodiment is represented based on the ((II)-4-A)-thconfiguration of the present invention, in the semiconductor lightemitting device of the sixteenth embodiment, the impurity for causingthe first compound semiconductor layer 21 to have the first conductivitytype (p-type) is different from the impurity for causing the thirdcompound semiconductor layer 43 to have the first conductivity type(p-type).

More specifically, in the semiconductor light emitting device of thesixteenth embodiment, the respective layers have the configuration shownin Table 13A or Table 13B shown below. In the example shown in Table13A, the third compound semiconductor layer 43 is stacked on the fourthcompound semiconductor layer 44. In the example shown in Table 13B, thefourth compound semiconductor layer 44 is stacked on the third compoundsemiconductor layer 43.

TABLE 13A (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Second burying layer 31B n-Al_(0.47)Ga_(0.53)As:Si First burying layer 31A n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Se Adjustment layer 30n-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer 32 n-GaAs: Se (or Si)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Se isformed between the third compound semiconductor layer 43 and the firstburying layer 31A (the partial portion of the first burying layer 31A inthe vicinity of the interface with the third compound semiconductorlayer 43 corresponds to this fifth compound semiconductor layer).

TABLE 13B (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Second burying layer 31B n-Al_(0.47)Ga_(0.53)As:Si First burying layer 31A n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: C Adjustment layer 30n-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer 32 n-GaAs: Se (or Si)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The first burying layer 31Ais formed subsequently to the fourth compound semiconductor layer 44 ina continuous manner, and a boundary does not exist between the firstburying layer 31A and the fourth compound semiconductor layer 44substantially.

Also in the sixteenth embodiment, at the timing when the formation of alight emitting part 20 is completed in a step similar to [Step-120] ofthe first embodiment, the sectional shape of the light emitting part 20obtained when the center part of the light emitting part 20 is cut alonga virtual plane perpendicular to the axis line of the light emittingpart 20 is a triangle. At this time, the sectional shape of the lightemitting part 20 obtained when the end part of the light emitting part20 is cut along a virtual plane perpendicular to the axis line of thelight emitting part 20 is a trapezoid. Therefore, in the formation ofthe current block layer 40 (the fourth compound semiconductor layer 44and the third compound semiconductor layer 43), the current block layer40 is formed only on the side surfaces of the light emitting part 20 atthe center part of the light emitting part 20. At this time, at the endparts of the light emitting part 20, in addition to the formation of thecurrent block layer 40 on the side surfaces of the light emitting part20, a deposited layer 40″ having the same multilayer structure as thatof the current block layer 40 is formed above the top surface of thelight emitting part 20. Subsequently to the formation of the currentblock layer 40, the first burying layer 31A is so formed as to cover theside surfaces of the light emitting part 20 and the side surfaces of atleast one layer of the deposited layer 40″ stacked above the lightemitting part 20, at both the end parts in particular. Subsequently, atthe timing of the completion of the covering of at least the sidesurfaces of the light emitting part 20 and the side surfaces of acompound semiconductor layer 30′ by the first burying layer 31A, theformation of the second burying layer 31B is started, so that the entiresurface is covered by the second burying layer 31B. If a compoundsemiconductor layer of the first conductivity type is included in thedeposited layer 40″ particularly as above, it is desirable that theburying layer 31 of the second conductivity type (e.g. the burying layer31B) whose impurity substitution site does not compete with the impuritysubstitution site in this compound semiconductor layer of the firstconductivity type included in the deposited layer 40″ be in contact withat least a part of the side surface of the deposited layer 40″. Thisstructure allows the impurity of the second conductivity type in theburying layer 31 (e.g. the burying layer 31B) to diffuse from the atleast a part of the side surface of the deposited layer 40″. This makesit possible to initially carry out conductivity type compensation forthe compound semiconductor layer of the first conductivity type that isincluded in the deposited layer 40″ and causes the current blocking, andthus turn this compound semiconductor layer of the first conductivitytype to a layer of the second conductivity type. At this time, theimpurity for causing the second burying layer 31B to have the secondconductivity type is such that the substitution site of the impurity inthe second burying layer 31B (the site occupied by a group III atom, inthe sixteenth embodiment) does not compete with the substitution site ofthe impurity in the third compound semiconductor layer (the siteoccupied by a group V atom, in the sixteenth embodiment) for causing thethird compound semiconductor layer 43 to have the first conductivitytype (see Table 13A or Table 13B). Therefore, e.g. the impurity forcausing the second burying layer 31B that is deposited to a largethickness so that the apex may be finally covered to have the secondconductivity type diffuses into a deposited layer 43″ of the thirdcompound semiconductor layer, having the first conductivity type andformed above the top surface at both the end parts of the light emittingpart 20. This diffusion turns the deposited layer 43″ of the thirdcompound semiconductor layer to a deposited layer 43′ of the thirdcompound semiconductor layer, having the second conductivity type. As aresult, all of the compound semiconductor layers located above the lightemitting part 20 at both the end parts of the light emitting part 20have the second conductivity type. Therefore, the deposited layer havingthe same multilayer structure as that of the current block layer 40 doesnot exist above the top surface of the multilayer structure of the lightemitting part 20, and the current injection path to the active layer isnot limited to the {111}B side surface (contact surface). This allowsensured avoidance of the occurrence of a problem that the electricresistance is increased and thus the heat generation and the currentconsumption are increased, and hence a problem that the light emissionefficiency of the semiconductor light emitting device is decreased.

Seventeenth Embodiment

The seventeenth embodiment is a modification of the fourteenthembodiment and the sixteenth embodiment, and relates to the((II)-1-D)-th configuration of the present invention and the((II)-2-D)-th configuration of the present invention.

Specifically, as shown in FIG. 24A as a conceptual diagram of the endparts of the light emitting part and FIG. 24B as a conceptual diagram ofthe center part of the light emitting part, when the semiconductor lightemitting device of the seventeenth embodiment is represented based onthe ((II)-1-D)-th configuration of the present invention, in thesemiconductor light emitting device of the seventeenth embodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, a fourth compoundsemiconductor layer, a first burying layer, and a second burying layerare composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom.

Furthermore, when the semiconductor light emitting device of theseventeenth embodiment is represented based on the ((II)-2-D)-thconfiguration of the present invention, in the semiconductor lightemitting device of the seventeenth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group IV impurity.

More specifically, in the semiconductor light emitting device of theseventeenth embodiment, the respective layers have the configurationshown in Table 14A or Table 14B shown below. In the example shown inTable 14A, the third compound semiconductor layer is stacked on thefourth compound semiconductor layer. In the example shown in Table 14B,the fourth compound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 14A (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: Si Firstburying layer n-Al_(0.47)Ga_(0.53)As: Se Third compound semiconductorlayer p-Al_(0.47)Ga_(0.53)As: C Fourth compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Se Adjustment layer n-Al_(0.47)Ga_(0.53)As: Se(Whole) Contact layer n-GaAs: Se (or Si) (Note 1) The adjustment layeris formed subsequently to the 2A-th compound semiconductor layer. (Note2) The fourth compound semiconductor layer is formed subsequently to theadjustment layer in a continuous manner, and a boundary does not existbetween the fourth compound semiconductor layer and the adjustment layersubstantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Se isformed between the third compound semiconductor layer and the firstburying layer (the partial portion of the first burying layer in thevicinity of the interface with the third compound semiconductor layercorresponds to this fifth compound semiconductor layer).

TABLE 14B (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: Si Firstburying layer n-Al_(0.47)Ga_(0.53)As: Se Fourth compound semiconductorlayer n-Al_(0.47)Ga_(0.53)As: Se Third compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: C Adjustment layer n-Al_(0.47)Ga_(0.53)As: Se(Whole) Contact layer n-GaAs: Se (or Si) (Note 1) The adjustment layeris formed subsequently to the 2A-th compound semiconductor layer. (Note2) The first burying layer is formed subsequently to the fourth compoundsemiconductor layer in a continuous manner, and a boundary does notexist between the first burying layer and the fourth compoundsemiconductor layer substantially.

Eighteenth Embodiment

The eighteenth embodiment relates to the ((II)-1-a)-th configuration ofthe present invention, the ((II)-3-a)-th configuration of the presentinvention, and the ((II)-4-a)-th configuration of the present invention.

Specifically, as shown in FIG. 25A as a conceptual diagram of the endparts of the light emitting part and FIG. 25B as a conceptual diagram ofthe center part of the light emitting part, when the semiconductor lightemitting device of the eighteenth embodiment is represented based on the((II)-1-a)-th configuration of the present invention, in thesemiconductor light emitting device of the eighteenth embodiment,

a first compound semiconductor layer 21, second compound semiconductorlayers 22A and 22B, a current block layer 40 (a fourth compoundsemiconductor layer 44 and a third compound semiconductor layer 43), afirst burying layer, and a second burying layer are composed of a III-Vcompound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group V atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group IIIatom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupV atom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom. Schematic partial sectional views ofthe semiconductor light emitting device of the eighteenth embodiment arethe same as those shown in FIGS. 49 and 50.

When the semiconductor light emitting device of the eighteenthembodiment is represented based on the ((II)-3-a)-th configuration ofthe present invention, in the semiconductor light emitting device of theeighteenth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the current block layer 40 (the fourthcompound semiconductor layer 44 and the third compound semiconductorlayer 43), the first burying layer, and the second burying layer arecomposed of a III-V compound semiconductor,

the impurity for causing the second compound semiconductor layers 22Aand 22B to be the p-type as the second conductivity type is a group IIimpurity,

the impurity for causing the fourth compound semiconductor layer 44 tobe the p-type as the second conductivity type is carbon (C),

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is a group II impurity.

Furthermore, when the semiconductor light emitting device of theeighteenth embodiment is represented based on the ((II)-4-a)-thconfiguration of the present invention, in the semiconductor lightemitting device of the eighteenth embodiment, the impurity for causingthe second compound semiconductor layers 22A and 22B to have the secondconductivity type (p-type) is different from the impurity for causingthe fourth compound semiconductor layer 44 to have the secondconductivity type (p-type).

More specifically, in the semiconductor light emitting device of theeighteenth embodiment, the respective layers have the configurationshown in Table 15A or Table 15B shown below. In the example shown inTable 15A, the third compound semiconductor layer 43 is stacked on thefourth compound semiconductor layer 44. In the example shown in Table15B, the fourth compound semiconductor layer 44 is stacked on the thirdcompound semiconductor layer 43.

TABLE 15A (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Second burying layer 31B p-Al_(0.47)Ga_(0.53)As:Zn First burying layer 31A p-Al_(0.47)Ga_(0.53)As: C Third compoundsemiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: C Adjustment layer 30p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: C isformed between the third compound semiconductor layer 43 and the firstburying layer 31A (the partial portion of the first burying layer 31A inthe vicinity of the interface with the third compound semiconductorlayer 43 corresponds to this fifth compound semiconductor layer).

TABLE 15B (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Second burying layer 31B p-Al_(0.47)Ga_(0.53)As:Zn First burying layer 31A p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: C Third compoundsemiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Se Adjustment layer 30p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The first burying layer 31Ais formed subsequently to the fourth compound semiconductor layer 44 ina continuous manner, and a boundary does not exist between the firstburying layer 31A and the fourth compound semiconductor layer 44substantially.

Also in the eighteenth embodiment, at the timing when the formation of alight emitting part 20 is completed in a step similar to [Step-120] ofthe first embodiment, the sectional shape of the light emitting part 20obtained when the center part of the light emitting part 20 is cut alonga virtual plane perpendicular to the axis line of the light emittingpart 20 is a triangle. At this time, the sectional shape of the lightemitting part 20 obtained when the end part of the light emitting part20 is cut along a virtual plane perpendicular to the axis line of thelight emitting part 20 is a trapezoid. Therefore, in the formation ofthe current block layer 40 (the fourth compound semiconductor layer 44and the third compound semiconductor layer 43), the current block layer40 is formed only on the side surfaces of the light emitting part 20 atthe center part of the light emitting part 20. At this time, at the endparts of the light emitting part 20, in addition to the formation of thecurrent block layer 40 on the side surfaces of the light emitting part20, a deposited layer 40″ having the same multilayer structure as thatof the current block layer 40 is formed above the top surface of thelight emitting part 20. Subsequently to the formation of the currentblock layer 40, the first burying layer 31A is so formed as to cover theside surfaces of the light emitting part 20 and the side surfaces of atleast one layer of the deposited layer 40″ stacked above the lightemitting part 20, at both the end parts in particular. Subsequently, atthe timing of the completion of the covering of at least the sidesurfaces of the light emitting part 20 and the side surfaces of acompound semiconductor layer 30′ by the first burying layer 31A, theformation of the second burying layer 31B is started, so that the entiresurface is covered by the second burying layer 31B. If a compoundsemiconductor layer of the first conductivity type is included in thedeposited layer 40″ particularly as above, it is desirable that theburying layer 31 of the second conductivity type (e.g. the burying layer31B) whose impurity substitution site does not compete with the impuritysubstitution site in this compound semiconductor layer of the firstconductivity type included in the deposited layer 40″ be in contact withat least a part of the side surface of the deposited layer 40″. Thisstructure allows the impurity of the second conductivity type in theburying layer 31 (e.g. the burying layer 31B) to diffuse from the atleast a part of the side surface of the deposited layer 40″. This makesit possible to initially carry out conductivity type compensation forthe compound semiconductor layer of the first conductivity type that isincluded in the deposited layer 40″ and causes the current blocking, andthus turn this compound semiconductor layer of the first conductivitytype to a layer of the second conductivity type. At this time, theimpurity for causing the second burying layer 31B to have the secondconductivity type is such that the substitution site of the impurity inthe second burying layer 31B (the site occupied by a group III atom, inthe eighteenth embodiment) does not compete with the substitution siteof the impurity in the third compound semiconductor layer (the siteoccupied by a group V atom, in the eighteenth embodiment) for causingthe third compound semiconductor layer 43 to have the first conductivitytype (see Table 15A or Table 15B). Therefore, e.g. the impurity forcausing the second burying layer 31B that is deposited to a largethickness so that the apex may be finally covered to have the secondconductivity type diffuses into a deposited layer 43″ of the thirdcompound semiconductor layer, having the first conductivity type andformed above the top surface at both the end parts of the light emittingpart 20. This diffusion turns the deposited layer 43″ of the thirdcompound semiconductor layer to a deposited layer 43′ of the thirdcompound semiconductor layer, having the second conductivity type. As aresult, all of the compound semiconductor layers located above the lightemitting part 20 at both the end parts of the light emitting part 20have the second conductivity type. Therefore, the deposited layer havingthe same multilayer structure as that of the current block layer 40 doesnot exist above the top surface of the multilayer structure of the lightemitting part 20, and the current injection path to the active layer isnot limited to the {111}B side surface (contact surface). This allowsensured avoidance of the occurrence of a problem that the electricresistance is increased and thus the heat generation and the currentconsumption are increased, and hence a problem that the light emissionefficiency of the semiconductor light emitting device is decreased.

Nineteenth Embodiment

The nineteenth embodiment is a modification of the eighteenthembodiment, and relates to the ((II)-1-b)-th configuration of thepresent invention and the ((II)-3-b)-th configuration of the presentinvention.

Specifically, as shown in FIG. 26A as a conceptual diagram of the endparts of the light emitting part and FIG. 26B as a conceptual diagram ofthe center part of the light emitting part, when the semiconductor lightemitting device of the nineteenth embodiment is represented based on the((II)-1-b)-th configuration of the present invention, in thesemiconductor light emitting device of the nineteenth embodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, a fourth compoundsemiconductor layer, a first burying layer, and a second burying layerare composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group Vatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group V atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group III atom.

Furthermore, when the semiconductor light emitting device of thenineteenth embodiment is represented based on the ((II)-3-b)-thconfiguration of the present invention, in the semiconductor lightemitting device of the nineteenth embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity,

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the third compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity,

the impurity for causing the fourth compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C),

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and

the impurity for causing the second burying layer to be the p-type asthe second conductivity type is a group II impurity.

More specifically, in the semiconductor light emitting device of thenineteenth embodiment, the respective layers have the configurationshown in Table 16A or Table 16B shown below. In the example shown inTable 16A, the third compound semiconductor layer is stacked on thefourth compound semiconductor layer. In the example shown in Table 16B,the fourth compound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 16A (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] 1B-thcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 1A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Current block layer)Second burying layer p-Al_(0.47)Ga_(0.53)As: Zn First burying layerp-Al_(0.47)Ga_(0.53)As: C Third compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Se Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: C Adjustment layer p-Al_(0.47)Ga_(0.53)As: C(Whole) Contact layer p-GaAs: C (or Zn) (Note 1) The adjustment layer isformed subsequently to the 2A-th compound semiconductor layer. (Note 2)The fourth compound semiconductor layer is formed subsequently to theadjustment layer in a continuous manner, and a boundary does not existbetween the fourth compound semiconductor layer and the adjustment layersubstantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of p-Al_(0.47)Ga_(0.53)As: C isformed between the third compound semiconductor layer and the firstburying layer (the partial portion of the first burying layer 31A in thevicinity of the interface with the third compound semiconductor layercorresponds to this fifth compound semiconductor layer).

TABLE 16B (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] 1B-thcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 1A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Current block layer)Second burying layer p-Al_(0.47)Ga_(0.53)As: Zn First burying layerp-Al_(0.47)Ga_(0.53)As: C Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: C Third compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Se Adjustment layer p-Al_(0.47)Ga_(0.53)As: C(Whole) Contact layer p-GaAs: C (or Zn) (Note 1) The adjustment layer isformed subsequently to the 2A-th compound semiconductor layer. (Note 2)The first burying layer is formed subsequently to the fourth compoundsemiconductor layer in a continuous manner, and a boundary does notexist between the first burying layer and the fourth compoundsemiconductor layer substantially.

Twentieth Embodiment

The twentieth embodiment is also a modification of the eighteenthembodiment, and relates to the (1-c)-th configuration of the presentinvention, the (3-c)-th configuration of the present invention, and the(4-a)-th configuration of the present invention. In the twentiethembodiment and the twenty-first embodiment to be described later, theconductivity types are reversed from those in the eighteenth embodiment.That is, in the twentieth embodiment and the twenty-first embodiment tobe described later, the first conductivity type is the p-type and thesecond conductivity type is the n-type.

Specifically, as shown in FIG. 27A as a conceptual diagram of the endparts of the light emitting part and FIG. 27B as a conceptual diagram ofthe center part of the light emitting part, when the semiconductor lightemitting device of the twentieth embodiment is represented based on the((II)-1-c)-th configuration of the present invention, in thesemiconductor light emitting device of the twentieth embodiment,

a first compound semiconductor layer 21, second compound semiconductorlayers 22A and 22B, a current block layer 40 (a third compoundsemiconductor layer 43 and a fourth compound semiconductor layer 44), afirst burying layer, and a second burying layer are composed of a III-Vcompound semiconductor,

the substitution site of the impurity in the first compoundsemiconductor layer 21 is the site occupied by a group III atom,

the substitution site of the impurity in the second compoundsemiconductor layers 22A and 22B is the site occupied by a group V atom,

the substitution site of the impurity in the third compoundsemiconductor layer 43 and the substitution site of the impurity in thefourth compound semiconductor layer 44 are the site occupied by a groupIII atom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom. Schematic partial sectional views ofthe semiconductor light emitting device of the twentieth embodiment arethe same as those shown in FIGS. 55 and 56.

Furthermore, when the semiconductor light emitting device of thetwentieth embodiment is represented based on the ((II)-3-c)-thconfiguration of the present invention, in the semiconductor lightemitting device of the twentieth embodiment,

the first compound semiconductor layer 21, the second compoundsemiconductor layers 22A and 22B, the current block layer 40 (the thirdcompound semiconductor layer 43 and the fourth compound semiconductorlayer 44), the first burying layer, and the second burying layer arecomposed of a III-V compound semiconductor,

the impurity for causing the second compound semiconductor layers 22Aand 22B to be the n-type as the second conductivity type is a group VIimpurity,

the impurity for causing the fourth compound semiconductor layer 44 tobe the n-type as the second conductivity type is a group IV impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group VI impurity.

Furthermore, when the semiconductor light emitting device of thetwentieth embodiment is represented based on the ((II)-4-a)-thconfiguration of the present invention, in the semiconductor lightemitting device of the twentieth embodiment, the impurity for causingthe second compound semiconductor layers 22A and 22B to have the secondconductivity type (n-type) is different from the impurity for causingthe fourth compound semiconductor layer 44 to have the secondconductivity type (n-type).

More specifically, in the semiconductor light emitting device of thetwentieth embodiment, the respective layers have the configuration shownin Table 17A or Table 17B shown below. In the example shown in Table17A, the third compound semiconductor layer 43 is stacked on the fourthcompound semiconductor layer 44. In the example shown in Table 17B, thefourth compound semiconductor layer 44 is stacked on the third compoundsemiconductor layer 43.

TABLE 17A (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Second burying layer 31B n-Al_(0.47)Ga_(0.53)As:Se First burying layer 31A n-Al_(0.47)Ga_(0.53)As: Si Third compoundsemiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Si Adjustment layer 30n-Al_(0.47)Ga_(0.53)As: Si (Whole) Contact layer 32 n-GaAs: Si (or Se)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between the fourthcompound semiconductor layer 44 and the adjustment layer 30substantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Si isformed between the third compound semiconductor layer 43 and the firstburying layer 31A (the partial portion of the first burying layer 31A inthe vicinity of the interface with the third compound semiconductorlayer 43 corresponds to this fifth compound semiconductor layer).

TABLE 17B (Configuration of light emitting part) Second compoundsemiconductor layer 22B n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer 22A n-Al_(0.4)Ga_(0.6)As: Se Active layer 23 [Activelayer-B] First compound semiconductor layer 21 p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Second burying layer 31B n-Al_(0.47)Ga_(0.53)As:Se First burying layer 31A n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer 44 n-Al_(0.47)Ga_(0.53)As: Si Third compoundsemiconductor layer 43 p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer 30n-Al_(0.47)Ga_(0.53)As: Si (Whole) Contact layer 32 n-GaAs: Si (or Se)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The first burying layer 31Ais formed subsequently to the fourth compound semiconductor layer 44 ina continuous manner, and a boundary does not exist between the firstburying layer 31A and the fourth compound semiconductor layer 44substantially.

Also in the twentieth embodiment, at the timing when the formation of alight emitting part 20 is completed in a step similar to [Step-120] ofthe first embodiment, the sectional shape of the light emitting part 20obtained when the center part of the light emitting part 20 is cut alonga virtual plane perpendicular to the axis line of the light emittingpart 20 is a triangle. At this time, the sectional shape of the lightemitting part 20 obtained when the end part of the light emitting part20 is cut along a virtual plane perpendicular to the axis line of thelight emitting part 20 is a trapezoid. Therefore, in the formation ofthe current block layer 40 (the fourth compound semiconductor layer 44and the third compound semiconductor layer 43), the current block layer40 is formed only on the side surfaces of the light emitting part 20 atthe center part of the light emitting part 20. At this time, at the endparts of the light emitting part 20, in addition to the formation of thecurrent block layer 40 on the side surfaces of the light emitting part20, a deposited layer 40″ having the same multilayer structure as thatof the current block layer 40 is formed above the top surface of thelight emitting part 20. Subsequently to the formation of the currentblock layer 40, the first burying layer 31A is so formed as to cover theside surfaces of the light emitting part 20 and the side surfaces of atleast one layer of the deposited layer 40″ stacked above the lightemitting part 20, at both the end parts in particular. Subsequently, atthe timing of the completion of the covering of at least the sidesurfaces of the light emitting part 20 and the side surfaces of acompound semiconductor layer 30′ by the first burying layer 31A, theformation of the second burying layer 31B is started, so that the entiresurface is covered by the second burying layer 31B. If a compoundsemiconductor layer of the first conductivity type is included in thedeposited layer 40″ particularly as above, it is desirable that theburying layer 31 of the second conductivity type (e.g. the burying layer31B) whose impurity substitution site does not compete with the impuritysubstitution site in this compound semiconductor layer of the firstconductivity type included in the deposited layer 40″ be in contact withat least a part of the side surface of the deposited layer 40″. Thisstructure allows the impurity of the second conductivity type in theburying layer 31 (e.g. the burying layer 31B) to diffuse from the atleast a part of the side surface of the deposited layer 40″. This makesit possible to initially carry out conductivity type compensation forthe compound semiconductor layer of the first conductivity type that isincluded in the deposited layer 40″ and causes the current blocking, andthus turn this compound semiconductor layer of the first conductivitytype to a layer of the second conductivity type. At this time, theimpurity for causing the second burying layer 31B to have the secondconductivity type is such that the substitution site of the impurity inthe second burying layer 31B (the site occupied by a group V atom, inthe twentieth embodiment) does not compete with the substitution site ofthe impurity in the third compound semiconductor layer (the siteoccupied by a group III atom, in the twentieth embodiment) for causingthe third compound semiconductor layer 43 to have the first conductivitytype (see Table 17A or Table 17B). Therefore, e.g. the impurity forcausing the second burying layer 31B that is deposited to a largethickness so that the apex may be finally covered to have the secondconductivity type diffuses into a deposited layer 43″ of the thirdcompound semiconductor layer, having the first conductivity type andformed above the top surface at both the end parts of the light emittingpart 20. This diffusion turns the deposited layer 43″ of the thirdcompound semiconductor layer to a deposited layer 43′ of the thirdcompound semiconductor layer, having the second conductivity type. As aresult, all of the compound semiconductor layers located above the lightemitting part 20 at both the end parts of the light emitting part 20have the second conductivity type. Therefore, the deposited layer havingthe same multilayer structure as that of the current block layer 40 doesnot exist above the top surface of the multilayer structure of the lightemitting part 20, and the current injection path to the active layer isnot limited to the {111}B side surface (contact surface). This allowsensured avoidance of the occurrence of a problem that the electricresistance is increased and thus the heat generation and the currentconsumption are increased, and hence a problem that the light emissionefficiency of the semiconductor light emitting device is decreased.

Twenty-First Embodiment

The twenty-first embodiment is a modification of the eighteenthembodiment and the twentieth embodiment, and relates to the((II)-1-d)-th configuration of the present invention and the((II)-3-d)-th configuration of the present invention.

Specifically, as shown in FIG. 28A as a conceptual diagram of the endparts of the light emitting part and FIG. 28B as a conceptual diagram ofthe center part of the light emitting part, when the semiconductor lightemitting device of the twenty-first embodiment is represented based onthe ((II)-1-d)-th configuration of the present invention, in thesemiconductor light emitting device of the twenty-first embodiment,

a first compound semiconductor layer, a second compound semiconductorlayer, a third compound semiconductor layer, a fourth compoundsemiconductor layer, a first burying layer, and a second burying layerare composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the substitution site of the impurity in the 1A-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group V atom,

the substitution site of the impurity in the 2A-th compoundsemiconductor layer is the site occupied by a group III atom,

the substitution site of the impurity in the third compoundsemiconductor layer and the substitution site of the impurity in thefourth compound semiconductor layer are the site occupied by a group IIIatom,

the substitution site of the impurity in the first burying layer is thesite occupied by a group III atom, and

the substitution site of the impurity in the second burying layer is thesite occupied by a group V atom.

Furthermore, when the semiconductor light emitting device of thetwenty-first embodiment is represented based on the ((II)-3-d)-thconfiguration of the present invention, in the semiconductor lightemitting device of the twenty-first embodiment,

the first compound semiconductor layer, the second compoundsemiconductor layer, the third compound semiconductor layer, the fourthcompound semiconductor layer, the first burying layer, and the secondburying layer are composed of a III-V compound semiconductor,

the first compound semiconductor layer is composed of the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith the active layer,

the second compound semiconductor layer is composed of the 2B-thcompound semiconductor layer in contact with the active layer and the2A-th compound semiconductor layer provided on the 2B-th compoundsemiconductor layer,

the impurity for causing the 1A-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity,

the impurity for causing the 2A-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the third compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity,

the impurity for causing the fourth compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity,

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and

the impurity for causing the second burying layer to be the n-type asthe second conductivity type is a group VI impurity.

More specifically, in the semiconductor light emitting device of thetwenty-first embodiment, the respective layers have the configurationshown in Table 18A or Table 18B shown below. In the example shown inTable 18A, the third compound semiconductor layer is stacked on thefourth compound semiconductor layer. In the example shown in Table 18B,the fourth compound semiconductor layer is stacked on the third compoundsemiconductor layer.

TABLE 18A (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: Se Firstburying layer n-Al_(0.47)Ga_(0.53)As: Si Third compound semiconductorlayer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Si Adjustment layer n-Al_(0.47)Ga_(0.53)As: Si(Whole) Contact layer n-GaAs: Si (or Se) (Note 1) The adjustment layeris formed subsequently to the 2A-th compound semiconductor layer. (Note2) The fourth compound semiconductor layer is formed subsequently to theadjustment layer in a continuous manner, and a boundary does not existbetween the fourth compound semiconductor layer and the adjustment layersubstantially. (Note 3) It is also possible to consider that a fifthcompound semiconductor layer composed of n-Al_(0.47)Ga_(0.53)As: Si isformed between the third compound semiconductor layer and the firstburying layer (the partial portion of the first burying layer in thevicinity of the interface with the third compound semiconductor layercorresponds to this fifth compound semiconductor layer).

TABLE 18B (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: Se Firstburying layer n-Al_(0.47)Ga_(0.53)As: Si Fourth compound semiconductorlayer n-Al_(0.47)Ga_(0.53)As: Si Third compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer n-Al_(0.47)Ga_(0.53)As: Si(Whole) Contact layer n-GaAs: Si (or Se) (Note 1) The adjustment layeris formed subsequently to the 2A-th compound semiconductor layer. (Note2) The first burying layer is formed subsequently to the fourth compoundsemiconductor layer in a continuous manner, and a boundary does notexist between the first burying layer and the fourth compoundsemiconductor layer substantially.

Twenty-Second Embodiment

The twenty-second embodiment relates to the semiconductor light emittingdevice according to the ((II)-5-th) configuration (specifically, the((II)-5-A-1)-th configuration) of the present invention. As shown inFIG. 29A as a conceptual diagram of the end parts of the light emittingpart, FIG. 29B as a conceptual diagram of the center part of the lightemitting part, FIGS. 49 and 50 as schematic partial sectional views, andFIGS. 51A to 51C as enlarged schematic partial sectional views, thesemiconductor light emitting device of the twenty-second embodimentincludes

(A) a light emitting part 20 formed of a multilayer structure arisingfrom sequential stacking of a first compound semiconductor layer 21 of afirst conductivity type (n-type, in the twenty-second embodiment), anactive layer 23, and a second compound semiconductor layer 22 of asecond conductivity type (p-type, in the twenty-second embodiment), and

(B) a current block layer 40 provided in contact with the side surfaceof the light emitting part 20.

The current block layer 40 has the same configuration and structure asthat of the current block layer 40 in the thirteenth embodiment, and thepositional relationship between the current block layer 40 and the lightemitting part 20 is the same as that in the thirteenth embodiment.

Also in the semiconductor light emitting device of the twenty-secondembodiment, the first compound semiconductor layer 21, the secondcompound semiconductor layer 22, the fourth compound semiconductor layer44, and the third compound semiconductor layer 43 are composed of aIII-V compound semiconductor. Furthermore, as described later, a 1A-thcompound semiconductor layer 21A, a 1B-th compound semiconductor layer21B, the second compound semiconductor layer 22, the fourth compoundsemiconductor layer 44, and the third compound semiconductor layer 43are composed of a III-V compound semiconductor. In addition, the firstcompound semiconductor layer 21, a 2A-th compound semiconductor layer22A, a 2B-th compound semiconductor layer 22B, the fourth compoundsemiconductor layer 44, the third compound semiconductor layer 43, afirst burying layer 31A, and a second burying layer 31B are composed ofa III-V compound semiconductor.

In the twenty-second embodiment, the substitution site of the impurityin the first compound semiconductor layer 21, the substitution site ofthe impurity in the second compound semiconductor layer 22, thesubstitution site of the impurity in the fourth compound semiconductorlayer 44, and the substitution site of the impurity in the thirdcompound semiconductor layer 43 are the site occupied by a group IIIatom. The substitution site of the impurity in the first burying layeris the site occupied by a group III atom, and the substitution site ofthe impurity in the second burying layer is the site occupied by a groupV atom. The impurity for causing the first compound semiconductor layer21 and the third compound semiconductor layer 43 to be the n-type as thefirst conductivity type is a group IV impurity (specifically, silicon,Si). The impurity for causing the second compound semiconductor layer 22and the fourth compound semiconductor layer 44 to be the p-type as thesecond conductivity type is a group II impurity (specifically, zinc,Zn). The impurity for causing the first burying layer 31A to be thep-type as the second conductivity type is a group II impurity(specifically, zinc, Zn). The impurity for causing the second buryinglayer 31B to be the p-type as the second conductivity type is carbon(C).

More specifically, in the semiconductor light emitting device of thetwenty-second embodiment, the respective layers have the configurationshown in Table 19A shown below.

TABLE 19A (Configuration of light emitting part) Second compoundsemiconductor layer 22B p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer 22A p-Al_(0.4)Ga_(0.6)As: Zn Active layer 23 [Activelayer-A] First compound semiconductor layer 21 n-Al_(0.4)Ga_(0.6)As: Si(Current block layer) Second burying layer 31B p-Al_(0.47)Ga_(0.53)As: CFirst burying layer 31A p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer 43 n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer 44 p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer 30p-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)(Note 1) The adjustment layer 30 is formed subsequently to the secondcompound semiconductor layer 22B. (Note 2) The fourth compoundsemiconductor layer 44 is formed subsequently to the adjustment layer 30in a continuous manner, and a boundary does not exist between theadjustment layer 30 and the fourth compound semiconductor layer 44substantially.

Also in the twenty-second embodiment, at the timing when the formationof the light emitting part 20 is completed in a step similar to[Step-120] of the first embodiment, the sectional shape of the lightemitting part 20 obtained when the center part of the light emittingpart 20 is cut along a virtual plane perpendicular to the axis line ofthe light emitting part 20 is a triangle. At this time, the sectionalshape of the light emitting part 20 obtained when the end part of thelight emitting part 20 is cut along a virtual plane perpendicular to theaxis line of the light emitting part 20 is a trapezoid. Therefore, inthe formation of the current block layer 40 (the fourth compoundsemiconductor layer 44 and the third compound semiconductor layer 43),the current block layer 40 is formed only on the side surfaces of thelight emitting part 20 at the center part of the light emitting part 20.At this time, at the end parts of the light emitting part 20, inaddition to the formation of the current block layer 40 on the sidesurfaces of the light emitting part 20, a deposited layer 40″ having thesame multilayer structure as that of the current block layer 40 isformed above the top surface of the light emitting part 20. Subsequentlyto the formation of the current block layer 40, the first burying layer31A is so formed as to cover the side surfaces of the light emittingpart 20 and the side surfaces of at least one layer of the depositedlayer 40″ stacked above the light emitting part 20, at both the endparts in particular. Subsequently, at the timing of the completion ofthe covering of at least the side surfaces of the light emitting part 20and the side surfaces of a compound semiconductor layer 30′ by the firstburying layer 31A, the formation of the second burying layer 31B isstarted, so that the entire surface is covered by the second buryinglayer 31B. If a compound semiconductor layer of the first conductivitytype is included in the deposited layer 40″ particularly as above, it isdesirable that the burying layer 31 of the second conductivity type(e.g. the burying layer 31B) whose impurity substitution site does notcompete with the impurity substitution site in this compoundsemiconductor layer of the first conductivity type included in thedeposited layer 40″ be in contact with at least a part of the sidesurface of the deposited layer 40″. This structure allows the impurityof the second conductivity type in the burying layer 31 (e.g. theburying layer 31B) to diffuse from the at least a part of the sidesurface of the deposited layer 40″. This makes it possible to initiallycarry out conductivity type compensation for the compound semiconductorlayer of the first conductivity type that is included in the depositedlayer 40″ and causes the current blocking, and thus turn this compoundsemiconductor layer of the first conductivity type to a layer of thesecond conductivity type. At this time, the impurity for causing thesecond burying layer 31B to have the second conductivity type is suchthat the substitution site of the impurity in the second burying layer31B (the site occupied by a group V atom, in the twenty-secondembodiment) does not compete with the substitution site of the impurityin the third compound semiconductor layer (the site occupied by a groupIII atom, in the twenty-second embodiment) for causing the thirdcompound semiconductor layer 43 to have the first conductivity type (seeTable 19A or Table 19B). Therefore, e.g. the impurity for causing thesecond burying layer 31B that is deposited to a large thickness so thatthe apex may be finally covered to have the second conductivity typediffuses into a deposited layer 43″ of the third compound semiconductorlayer, having the first conductivity type and formed above the topsurface at both the end parts of the light emitting part 20. Thisdiffusion turns the deposited layer 43″ of the third compoundsemiconductor layer to a deposited layer 43′ of the third compoundsemiconductor layer, having the second conductivity type. As a result,all of the compound semiconductor layers located above the lightemitting part 20 at both the end parts of the light emitting part 20have the second conductivity type. Therefore, the deposited layer havingthe same multilayer structure as that of the current block layer 40 doesnot exist above the top surface of the multilayer structure of the lightemitting part 20, and the current injection path to the active layer isnot limited to the {111}B side surface (contact surface). This allowsensured avoidance of the occurrence of a problem that the electricresistance is increased and thus the heat generation and the currentconsumption are increased, and hence a problem that the light emissionefficiency of the semiconductor light emitting device is decreased.

Except for the above-described points, the semiconductor light emittingdevice of the twenty-second embodiment has the same configuration andstructure as those of the semiconductor light emitting device of thefourteenth embodiment basically, and therefore the detailed descriptionthereof is omitted.

Modification examples of the semiconductor light emitting device of thetwenty-second embodiment will be described below.

A modification example of the semiconductor light emitting device of thetwenty-second embodiment is shown in FIG. 30A as a conceptual diagram ofthe end parts of the light emitting part and FIG. 30B as a conceptualdiagram of the center part of the light emitting part. This modificationexample corresponds to the semiconductor light emitting device accordingto the ((II)-5-A-2)-th configuration of the present invention.Specifically, in this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity (specifically, Si), and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group VI impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19B shown below. Table 19Bis given the same notes as (Note 1) and (Note 2) of Table 19A (thisapplies also to Tables 9C to 9J to be described later).

TABLE 19B (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: SeFirst burying layer n-Al_(0.47)Ga_(0.53)As: Si Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

A modification example of the semiconductor light emitting device of thetwenty-second embodiment is shown in FIG. 31A as a conceptual diagram ofthe end parts of the light emitting part and FIG. 31B as a conceptualdiagram of the center part of the light emitting part. Furthermore,another modification example of the semiconductor light emitting deviceof the twenty-second embodiment is shown in FIG. 32A as a conceptualdiagram of the end parts of the light emitting part and FIG. 32B as aconceptual diagram of the center part of the light emitting part. Thesemodification examples correspond to the semiconductor light emittingdevice according to the ((II)-5-a)-th configuration of the presentinvention. In this semiconductor light emitting device, the substitutionsite of the impurity in the first compound semiconductor layer, thesubstitution site of the impurity in the second compound semiconductorlayer, the substitution site of the impurity in the fourth compoundsemiconductor layer, and the substitution site of the impurity in thethird compound semiconductor layer are the site occupied by a group Vatom. The substitution site of the impurity in the first burying layeris the site occupied by a group V atom, and the substitution site of theimpurity in the second burying layer is the site occupied by a group IIIatom.

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 31A and 31B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-a-1)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and the impurity for causing thesecond burying layer to be the p-type as the second conductivity type isa group II impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19C shown below.

TABLE 19C (Configuration of light emitting part) Second compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Second compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C Active layer [Activelayer-A] First compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se(Current block layer) Second burying layer p-Al_(0.47)Ga_(0.53)As: ZnFirst burying layer p-Al_(0.47)Ga_(0.53)As: C Third compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer 32 p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 32A and 32B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-a-2)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity (specifically, Se), and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group IV impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19D shown below.

TABLE 19D (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C(Current block layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: SiFirst burying layer n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

A modification example of the semiconductor light emitting device of thetwenty-second embodiment is shown in FIG. 33A as a conceptual diagram ofthe end parts of the light emitting part and FIG. 33B as a conceptualdiagram of the center part of the light emitting part. Furthermore,another modification example of the semiconductor light emitting deviceof the twenty-second embodiment is shown in FIG. 35A as a conceptualdiagram of the end parts of the light emitting part and FIG. 35B as aconceptual diagram of the center part of the light emitting part. Thesemodification examples correspond to the semiconductor light emittingdevice according to the ((II)-5-B)-th configuration of the presentinvention. In this semiconductor light emitting device,

the first compound semiconductor layer is composed of a 1A-th compoundsemiconductor layer and a 1B-th compound semiconductor layer that isprovided on the 1A-th compound semiconductor layer and is in contactwith an active layer, and

the impurity for causing the 1B-th compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the 1B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 1A-th compoundsemiconductor layer for causing the 1A-th compound semiconductor layerto have the first conductivity type, and does not compete with thesubstitution site of the impurity in the second compound semiconductorlayer for causing the second compound semiconductor layer to have thesecond conductivity type. The impurity for causing the 1A-th compoundsemiconductor layer to have the first conductivity type is such that thesubstitution site of the impurity in the 1A-th compound semiconductorlayer competes with the substitution site of the impurity in the fourthcompound semiconductor layer for causing the fourth compoundsemiconductor layer to have the second conductivity type. Specifically,the substitution site of the impurity in the 1A-th compoundsemiconductor layer, the substitution site of the impurity in the secondcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 1B-th compound semiconductor layer is the site occupied by a group Vatom. The substitution site of the impurity in the first burying layeris the site occupied by a group III atom.

The substitution site of the impurity in the second burying layer is thesite occupied by a group V atom.

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 33A and 33B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-B-1)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity (specifically, Si),

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group VI impurity(specifically, Se),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity (specifically, Zn), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and the impurity forcausing the second burying layer to be the p-type as the secondconductivity type is carbon (C).

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19E shown below.

TABLE 19E (Configuration of light emitting part) Second compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Second compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Activelayer-A] 1B-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se1A-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Si (Currentblock layer) Second burying layer p-Al_(0.47)Ga_(0.53)As: C Firstburying layer p-Al_(0.47)Ga_(0.53)As: Zn Third compound semiconductorlayer n-Al_(0.47)Ga_(0.53)As: Si Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: Zn Adjustment layer p-Al_(0.47)Ga_(0.53)As: Zn(Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 35A and 35B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-B-2)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is carbon (C),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity (specifically, Si), and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group VI impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19F shown below.

TABLE 19F (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn (Currentblock layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: Se Firstburying layer n-Al_(0.47)Ga_(0.53)As: Si Third compound semiconductorlayer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Si Adjustment layer n-Al_(0.47)Ga_(0.53)As: Se(Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the twenty-secondembodiment whose conceptual diagrams are shown in FIGS. 33A and 33B andFIGS. 35A and 35B are shown in FIGS. 34A and 34B and FIGS. 36A and 36B.In these further-modified examples,

a sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer and the1A-th compound semiconductor layer to have the first conductivity typeis such that the substitution site of the impurity in the sixth compoundsemiconductor layer competes with the substitution site of the impurityin the 1A-th compound semiconductor layer for causing the 1A-th compoundsemiconductor layer to have the first conductivity type (specifically, agroup IV impurity, Si, in FIGS. 34A and 34B, and a group II impurity,Zn, in FIGS. 36A and 36B), and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer. The bypass channel iscomposed of the first compound semiconductor layer (the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer), thesixth compound semiconductor layer, the fourth compound semiconductorlayer, the third compound semiconductor layer, and the second compoundsemiconductor layer. The pn junction interfaces are formed of thefollowing three interfaces: the interface between the sixth compoundsemiconductor layer and the fourth compound semiconductor layer; theinterface between the fourth compound semiconductor layer and the thirdcompound semiconductor layer; and the interface between the thirdcompound semiconductor layer and the side surface of the second compoundsemiconductor layer.

A modification example of the semiconductor light emitting device of thetwenty-second embodiment is shown in FIG. 37A as a conceptual diagram ofthe end parts of the light emitting part and FIG. 37B as a conceptualdiagram of the center part of the light emitting part. Furthermore,another modification example of the semiconductor light emitting deviceof the twenty-second embodiment is shown in FIG. 39A as a conceptualdiagram of the end parts of the light emitting part and FIG. 39B as aconceptual diagram of the center part of the light emitting part. Thesemodification examples correspond to the semiconductor light emittingdevice according to the ((II)-5-b)-th configuration of the presentinvention. In this semiconductor light emitting device, the substitutionsite of the impurity in the 1A-th compound semiconductor layer, thesubstitution site of the impurity in the second compound semiconductorlayer, the substitution site of the impurity in the fourth compoundsemiconductor layer, and the substitution site of the impurity in thethird compound semiconductor layer are the site occupied by a group Vatom. The substitution site of the impurity in the 1B-th compoundsemiconductor layer is the site occupied by a group III atom. Thesubstitution site of the impurity in the first burying layer is the siteoccupied by a group V atom, and the substitution site of the impurity inthe second burying layer is the site occupied by a group III atom.

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 37A and 37B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-b-1)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the 1B-th compound semiconductor layer to bethe n-type as the first conductivity type is a group IV impurity(specifically, Si),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and the impurity for causing thesecond burying layer to be the p-type as the second conductivity type isa group II impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19G shown below.

TABLE 19G (Configuration of light emitting part) Second compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Second compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C Active layer [Activelayer-A] 1B-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Si1A-th compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se (Currentblock layer) Second burying layer p-Al_(0.47)Ga_(0.53)As: Zn Firstburying layer p-Al_(0.47)Ga_(0.53)As: C Third compound semiconductorlayer n-Al_(0.47)Ga_(0.53)As: Se Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: C Adjustment layer p-Al_(0.47)Ga_(0.53)As: Zn(Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 39A and 39B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-b-2)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the 1A-th compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 1B-th compound semiconductor layer to bethe p-type as the first conductivity type is a group II impurity(specifically, Zn),

the impurity for causing the second compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity (specifically, Se), and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group IV impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19H shown below.

TABLE 19H (Configuration of light emitting part) Second compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Second compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] 1B-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn1A-th compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C (Currentblock layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: Si Firstburying layer n-Al_(0.47)Ga_(0.53)As: Se Third compound semiconductorlayer p-Al_(0.47)Ga_(0.53)As: C Fourth compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Se Adjustment layer n-Al_(0.47)Ga_(0.53)As: Se(Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the twenty-secondembodiment whose conceptual diagrams are shown in FIGS. 37A and 37B andFIGS. 39A and 39B are shown in FIGS. 38A and 38B and FIGS. 40A and 40B.Also in these further-modified examples,

the sixth compound semiconductor layer of the first conductivity type isprovided under the fourth compound semiconductor layer,

the impurity for causing the sixth compound semiconductor layer to havethe first conductivity type is such that the substitution site of theimpurity in the sixth compound semiconductor layer competes with thesubstitution site of the impurity in the 1A-th compound semiconductorlayer for causing the 1A-th compound semiconductor layer to have thefirst conductivity type (specifically, a group VI impurity, Se, in FIGS.38A and 38B, and carbon (C) in FIGS. 40A and 40B), and

the sixth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer (at least a part ofthe side surface of the 1A-th compound semiconductor layer and all ofthe side surface of the 1B-th compound semiconductor layer), and thethird compound semiconductor layer is in contact with the side surfaceof the second compound semiconductor layer. The bypass channel iscomposed of the first compound semiconductor layer (the 1A-th compoundsemiconductor layer and the 1B-th compound semiconductor layer), thesixth compound semiconductor layer, the fourth compound semiconductorlayer, the third compound semiconductor layer, and the second compoundsemiconductor layer. The pn junction interfaces are formed of thefollowing three interfaces: the interface between the sixth compoundsemiconductor layer and the fourth compound semiconductor layer; theinterface between the fourth compound semiconductor layer and the thirdcompound semiconductor layer; and the interface between the thirdcompound semiconductor layer and the side surface of the second compoundsemiconductor layer.

A modification example of the semiconductor light emitting device of thetwenty-second embodiment is shown in FIG. 41A as a conceptual diagram ofthe end parts of the light emitting part and FIG. 41B as a conceptualdiagram of the center part of the light emitting part. Furthermore,another modification example of the semiconductor light emitting deviceof the twenty-second embodiment is shown in FIG. 43A as a conceptualdiagram of the end parts of the light emitting part and FIG. 43B as aconceptual diagram of the center part of the light emitting part. Thesemodification examples correspond to the semiconductor light emittingdevice according to the ((II)-5-C)-th configuration of the presentinvention. In this semiconductor light emitting device,

the second compound semiconductor layer is composed of a 2B-th compoundsemiconductor layer in contact with the active layer and a 2A-thcompound semiconductor layer provided on the 2B-th compoundsemiconductor layer, and

the impurity for causing the 2B-th compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the 2B-th compound semiconductor layer does not compete withthe substitution site of the impurity in the 2A-th compoundsemiconductor layer for causing the 2A-th compound semiconductor layerto have the second conductivity type, and does not compete with thesubstitution site of the impurity in the first compound semiconductorlayer for causing the first compound semiconductor layer to have thefirst conductivity type. The impurity for causing the 2A-th compoundsemiconductor layer to have the second conductivity type is such thatthe substitution site of the impurity in the 2A-th compoundsemiconductor layer competes with the substitution site of the impurityin the third compound semiconductor layer for causing the third compoundsemiconductor layer to have the first conductivity type. Specifically,the substitution site of the impurity in the first compoundsemiconductor layer, the substitution site of the impurity in the 2A-thcompound semiconductor layer, the substitution site of the impurity inthe fourth compound semiconductor layer, and the substitution site ofthe impurity in the third compound semiconductor layer are the siteoccupied by a group III atom. The substitution site of the impurity inthe 2B-th compound semiconductor layer is the site occupied by a group Vatom. The substitution site of the impurity in the first burying layeris the site occupied by a group III atom. The substitution site of theimpurity in the second burying layer is the site occupied by a group Vatom.

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 41A and 41B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-C-1)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group IV impurity (specifically, Si),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is carbon (C), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is a group II impurity, and the impurity forcausing the second burying layer to be the p-type as the secondconductivity type is carbon (C).

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 191 shown below.

TABLE 19I (Configuration of light emitting part) 2B-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C Active layer [Activelayer-A] First compound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Si(Current block layer) Second burying layer p-Al_(0.47)Ga_(0.53)As: CFirst burying layer p-Al_(0.47)Ga_(0.53)As: Zn Third compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Fourth compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Adjustment layerp-Al_(0.47)Ga_(0.53)As: Zn (Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 43A and 43B correspond to the semiconductor light emitting deviceaccording to the ((II)5-C-2)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is a group II impurity (specifically, Zn),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group IV impurity (specifically, Si),

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group VI impurity(specifically, Se), and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group IV impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group VI impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19J shown below.

TABLE 19J (Configuration of light emitting part) 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: Zn(Current block layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: SeFirst burying layer n-Al_(0.47)Ga_(0.53)As: Si Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: Zn Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Si Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the twenty-secondembodiment whose conceptual diagrams are shown in FIGS. 41A and 41B andFIGS. 43A and 43B are shown in FIGS. 42A and 42B and FIGS. 44A and 44B.In these further-modified examples,

a fifth compound semiconductor layer of the second conductivity type isprovided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fifth compound semiconductor layer competes with thesubstitution site of the impurity in the 2A-th compound semiconductorlayer for causing the 2A-th compound semiconductor layer to have thesecond conductivity type (specifically, a group II impurity, Zn, inFIGS. 42A and 42B, and a group IV impurity, Si, in FIGS. 44A and 44B),and

the fourth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer and the fifth compoundsemiconductor layer is in contact with the side surface of the secondcompound semiconductor layer (at least a part of the side surface of the2A-th compound semiconductor layer and all of the side surface of the2B-th compound semiconductor layer). The bypass channel is composed ofthe first compound semiconductor layer, the fourth compoundsemiconductor layer, the third compound semiconductor layer, the fifthcompound semiconductor layer, and the second compound semiconductorlayer (the 2A-th compound semiconductor layer and the 2B-th compoundsemiconductor layer). The pn junction interfaces are formed of thefollowing three interfaces: the interface between the side surface ofthe first compound semiconductor layer and the fourth compoundsemiconductor layer; the interface between the fourth compoundsemiconductor layer and the third compound semiconductor layer; and theinterface between the third compound semiconductor layer and the fifthcompound semiconductor layer.

A modification example of the semiconductor light emitting device of thetwenty-second embodiment is shown in FIG. 45A as a conceptual diagram ofthe end parts of the light emitting part and FIG. 45B as a conceptualdiagram of the center part of the light emitting part. Furthermore,another modification example of the semiconductor light emitting deviceof the twenty-second embodiment is shown in FIG. 47A as a conceptualdiagram of the end parts of the light emitting part and FIG. 47B as aconceptual diagram of the center part of the light emitting part. Thesemodification examples correspond to the semiconductor light emittingdevice according to the ((II)-5-c)-th configuration of the presentinvention. In this semiconductor light emitting device, the substitutionsite of the impurity in the first compound semiconductor layer, thesubstitution site of the impurity in the 2A-th compound semiconductorlayer, the substitution site of the impurity in the fourth compoundsemiconductor layer, and the substitution site of the impurity in thethird compound semiconductor layer are the site occupied by a group Vatom. The substitution site of the impurity in the 2B-th compoundsemiconductor layer is the site occupied by a group III atom. Thesubstitution site of the impurity in the first burying layer is the siteoccupied by a group V atom, and the substitution site of the impurity inthe second burying layer is the site occupied by a group III atom.

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 45A and 45B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-c-1)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the n-type as the firstconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the p-type as the secondconductivity type is carbon (C),

the impurity for causing the 2B-th compound semiconductor layer to bethe p-type as the second conductivity type is a group II impurity(specifically, Zn), and

the impurity for causing the first burying layer to be the p-type as thesecond conductivity type is carbon (C), and the impurity for causing thesecond burying layer to be the p-type as the second conductivity type isa group II impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19K shown below.

TABLE 19K (Configuration of light emitting part) 2A-th compoundsemiconductor layer p-Al_(0.4)Ga_(0.6)As: C 2B-th compound semiconductorlayer p-Al_(0.4)Ga_(0.6)As: Zn Active layer [Active layer-A] Firstcompound semiconductor layer n-Al_(0.4)Ga_(0.6)As: Se (Current blocklayer) Second burying layer p-Al_(0.47)Ga_(0.53)As: Zn First buryinglayer p-Al_(0.47)Ga_(0.53)As: C Third compound semiconductor layern-Al_(0.47)Ga_(0.53)As: Se Fourth compound semiconductor layerp-Al_(0.47)Ga_(0.53)As: C Adjustment layer p-Al_(0.47)Ga_(0.53)As: Zn(Whole) Contact layer p-GaAs: Zn (or C)

The modification example of the semiconductor light emitting device ofthe twenty-second embodiment whose conceptual diagrams are shown inFIGS. 47A and 47B correspond to the semiconductor light emitting deviceaccording to the ((II)-5-c-2)-th configuration of the present invention.In this semiconductor light emitting device,

the impurity for causing the first compound semiconductor layer and thethird compound semiconductor layer to be the p-type as the firstconductivity type is carbon (C),

the impurity for causing the 2A-th compound semiconductor layer and thefourth compound semiconductor layer to be the n-type as the secondconductivity type is a group VI impurity (specifically, Se),

the impurity for causing the 2B-th compound semiconductor layer to bethe n-type as the second conductivity type is a group IV impurity(specifically, Si), and

the impurity for causing the first burying layer to be the n-type as thesecond conductivity type is a group VI impurity, and the impurity forcausing the second burying layer to be the n-type as the secondconductivity type is a group IV impurity.

More specifically, in this modification example of the semiconductorlight emitting device of the twenty-second embodiment, the respectivelayers have the configuration shown in Table 19L shown below.

TABLE 19L (Configuration of light emitting part) 2A-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Se 2B-th compoundsemiconductor layer n-Al_(0.4)Ga_(0.6)As: Si Active layer [Activelayer-B] First compound semiconductor layer p-Al_(0.4)Ga_(0.6)As: C(Current block layer) Second burying layer n-Al_(0.47)Ga_(0.53)As: SiFirst burying layer n-Al_(0.47)Ga_(0.53)As: Se Third compoundsemiconductor layer p-Al_(0.47)Ga_(0.53)As: C Fourth compoundsemiconductor layer n-Al_(0.47)Ga_(0.53)As: Se Adjustment layern-Al_(0.47)Ga_(0.53)As: Se (Whole) Contact layer p-GaAs: Zn (or C)

Conceptual diagrams of further-modified examples of the modificationexamples of the semiconductor light emitting device of the twenty-secondembodiment whose conceptual diagrams are shown in FIGS. 45A and 45B andFIGS. 47A and 27B are shown in FIGS. 46A and 46B and FIGS. 48A and 48B.Also in these further-modified examples,

the fifth compound semiconductor layer of the second conductivity typeis provided on the third compound semiconductor layer,

the impurity for causing the fifth compound semiconductor layer to havethe second conductivity type is such that the substitution site of theimpurity in the fifth compound semiconductor layer competes with thesubstitution site of the impurity in the 2A-th compound semiconductorlayer for causing the 2A-th compound semiconductor layer to have thesecond conductivity type (specifically, carbon in FIGS. 46A and 46B, anda group VI impurity, Se, in FIGS. 48A and 48B), and

the fourth compound semiconductor layer is in contact with the sidesurface of the first compound semiconductor layer and the fifth compoundsemiconductor layer is in contact with the side surface of the secondcompound semiconductor layer (at least a part of the side surface of the2A-th compound semiconductor layer and all of the side surface of the2B-th compound semiconductor layer). The bypass channel is composed ofthe first compound semiconductor layer, the fourth compoundsemiconductor layer, the third compound semiconductor layer, the fifthcompound semiconductor layer, and the second compound semiconductorlayer (the 2A-th compound semiconductor layer and the 2B-th compoundsemiconductor layer). The pn junction interfaces are formed of thefollowing three interfaces: the interface between the side surface ofthe first compound semiconductor layer and the fourth compoundsemiconductor layer; the interface between the fourth compoundsemiconductor layer and the third compound semiconductor layer; and theinterface between the third compound semiconductor layer and the fifthcompound semiconductor layer.

This is the end of the description of preferred embodiments of thepresent invention. The invention however is not limited to theseembodiments.

The structure of the first compound semiconductor layer in the fifthembodiment (see FIG. 7A) may be combined with the structure of thesecond compound semiconductor layer in the sixth embodiment (see FIG.8A). The structure of the second compound semiconductor layer in thefifth embodiment (see FIG. 7A) may be combined with the structure of thefirst compound semiconductor layer in the sixth embodiment (see FIG.8A). The structure of the first compound semiconductor layer in theseventh embodiment (see FIG. 9A) may be combined with the structure ofthe second compound semiconductor layer in the eighth embodiment (seeFIG. 10A). The structure of the second compound semiconductor layer inthe seventh embodiment (see FIG. 9A) may be combined with the structureof the first compound semiconductor layer in the eighth embodiment (seeFIG. 10A). Furthermore, the structure of the first compoundsemiconductor layer in the ninth embodiment (see FIG. 7B) may becombined with the structure of the second compound semiconductor layerin the tenth embodiment (see FIG. 8B). The structure of the secondcompound semiconductor layer in the ninth embodiment (see FIG. 7B) maybe combined with the structure of the first compound semiconductor layerin the tenth embodiment (see FIG. 8B). The structure of the firstcompound semiconductor layer in the eleventh embodiment (see FIG. 9B)may be combined with the structure of the second compound semiconductorlayer in the twelfth embodiment (see FIG. 10B). The structure of thesecond compound semiconductor layer in the eleventh embodiment (see FIG.9B) may be combined with the structure of the first compoundsemiconductor layer in the twelfth embodiment (see FIG. 10B).

The structure of the first compound semiconductor layer in thefourteenth embodiment (see FIGS. 21A and 21B) may be combined with thestructure of the second compound semiconductor layer in the fifteenthembodiment (see FIGS. 22A and 22B). The structure of the second compoundsemiconductor layer in the fourteenth embodiment (see FIGS. 21A and 21B)may be combined with the structure of the first compound semiconductorlayer in the fifteenth embodiment (see FIGS. 22A and 22B). The structureof the first compound semiconductor layer in the sixteenth embodiment(see FIGS. 23A and 23B) may be combined with the structure of the secondcompound semiconductor layer in the seventeenth embodiment (see FIGS.24A and 24B). The structure of the second compound semiconductor layerin the sixteenth embodiment (see FIGS. 23A and 23B) may be combined withthe structure of the first compound semiconductor layer in theseventeenth embodiment (see FIGS. 24A and 24B). Furthermore, thestructure of the first compound semiconductor layer in the eighteenthembodiment (see FIGS. 25A and 25B) may be combined with the structure ofthe second compound semiconductor layer in the nineteenth embodiment(see FIGS. 26A and 26B). The structure of the second compoundsemiconductor layer in the eighteenth embodiment (see FIGS. 25A and 25B)may be combined with the structure of the first compound semiconductorlayer in the nineteenth embodiment (see FIGS. 26A and 26B). Thestructure of the first compound semiconductor layer in the twentiethembodiment (see FIGS. 27A and 27B) may be combined with the structure ofthe second compound semiconductor layer in the twenty-first embodiment(see FIGS. 28A and 28B). The structure of the second compoundsemiconductor layer in the twentieth embodiment (see FIGS. 27A and 27B)may be combined with the structure of the first compound semiconductorlayer in the twenty-first embodiment (see FIGS. 28A and 28B).

Furthermore, it is also possible for the semiconductor light emittingdevices described for the fifth to twelfth and fourteenth totwenty-first embodiments to have the following configuration.Specifically,

the current block layer 40 further includes a fifth compoundsemiconductor layer of the second conductivity type,

the third compound semiconductor layer 43 is sandwiched by the fourthcompound semiconductor layer 44 and the fifth compound semiconductorlayer, and

the impurity for causing the third compound semiconductor layer 43 tohave the first conductivity type is such that the substitution site ofthe impurity in the third compound semiconductor layer 43 competes withthe substitution site of the impurity in the fifth compoundsemiconductor layer for causing the fifth compound semiconductor layerto have the second conductivity type.

In the fifth, sixth, ninth, and tenth embodiments, it is also possibleto regard the adjustment layer 30 as the fifth compound semiconductorlayer, and the burying layer 31 as the fifth compound semiconductorlayer although depending on the stacking state of the third compoundsemiconductor layer 43 and the fourth compound semiconductor layer 44.This applies also to the seventh, eighth, eleventh, and twelfthembodiments.

In the fourteenth, fifteenth, eighteenth, and nineteenth embodiments, itis also possible to regard the adjustment layer 30 as the fifth compoundsemiconductor layer, although depending on the stacking state of thethird compound semiconductor layer 43 and the fourth compoundsemiconductor layer 44. This applies also to the sixteenth, seventeenth,twentieth, and twenty-first embodiments.

In addition, it is also possible for the semiconductor light emittingdevices described for the fifth to twelfth and fourteenth totwenty-first embodiments to have the following configuration.Specifically,

the current block layer 40 further includes a sixth compoundsemiconductor layer of the first conductivity type,

the fourth compound semiconductor layer 44 is sandwiched by the thirdcompound semiconductor layer 43 and the sixth compound semiconductorlayer, and

the impurity for causing the fourth compound semiconductor layer 44 tohave the second conductivity type is such that the substitution site ofthe impurity in the fourth compound semiconductor layer 44 competes withthe substitution site of the impurity in the sixth compoundsemiconductor layer for causing the sixth compound semiconductor layerto have the first conductivity type.

In the fifth, sixth, ninth, and tenth embodiments, it is possible forthe current block layer 40 to have a three-layer structure arising fromthe stacking in the order of the third compound semiconductor layer 43(n-type)/the fourth compound semiconductor layer 44 (p-type)/the sixthcompound semiconductor layer (n-type). In addition, it is possible forthe current block layer 40 to have a three-layer structure arising fromthe stacking in the order of the sixth compound semiconductor layer(n-type)/the fourth compound semiconductor layer 44 (p-type)/the thirdcompound semiconductor layer 43 (n-type). Furthermore, also in theseventh, eighth, eleventh, and twelfth embodiments, it is possible forthe current block layer 40 to have a three-layer structure arising fromthe stacking in the order of the third compound semiconductor layer 43(p-type)/the fourth compound semiconductor layer 44 (n-type)/the sixthcompound semiconductor layer (p-type). In addition, it is possible forthe current block layer 40 to have a three-layer structure arising fromthe stacking in the order of the sixth compound semiconductor layer(p-type)/the fourth compound semiconductor layer 44 (n-type)/the thirdcompound semiconductor layer 43 (p-type).

In the fifth, seventh, ninth, and eleventh embodiments, the secondcompound semiconductor layer has the two-layer structure composed of thesecond compound semiconductor layer 22A and the second compoundsemiconductor layer 22B stacked in that order from the active layerside. In the sixth, eighth, tenth, and twelfth embodiments, the secondcompound semiconductor layer has the two-layer structure composed of the2A-th compound semiconductor layer and the 2B-th compound semiconductorlayer stacked in that order from the active layer side. In the formercase, the second compound semiconductor layer of the two-layer structureis defined based on the change of the band gap (or the refractiveindex). In the latter case, the second compound semiconductor layer ofthe two-layer structure is defined based on the change of the impuritysubstitution site. Therefore, regarding the multilayer structure of thesecond compound semiconductor layer described for the respectiveembodiments, if the second compound semiconductor layer has thetwo-layer structure composed of the 2A-th compound semiconductor layerand the 2B-th compound semiconductor layer in particular, the 2A-thcompound semiconductor layer can be regarded as the second compoundsemiconductor layer 22A and the 2B-th compound semiconductor layer canbe regarded as the second compound semiconductor layer 22B. In addition,for example, it is also possible that the 2A-th compound semiconductorlayer is formed of the multilayer structure composed of the secondcompound semiconductor layers 22A and 22B, and it is also possible thatthe 2B-th compound semiconductor layer is formed of the multilayerstructure composed of the second compound semiconductor layers 22A and22B.

In the fourteenth, fifteenth, eighteenth, and nineteenth embodiments, itis possible for the current block layer 40 to have a three-layerstructure arising from the stacking in the order of the third compoundsemiconductor layer 43 (n-type)/the fourth compound semiconductor layer44 (p-type)/the sixth compound semiconductor layer (n-type). Inaddition, it is possible for the current block layer 40 to have athree-layer structure arising from the stacking in the order of thesixth compound semiconductor layer (n-type)/the fourth compoundsemiconductor layer 44 (p-type)/the third compound semiconductor layer43 (n-type). Furthermore, also in the sixteenth, seventeenth, twentieth,and twenty-first embodiments, it is possible for the current block layer40 to have a three-layer structure arising from the stacking in theorder of the third compound semiconductor layer 43 (p-type)/the fourthcompound semiconductor layer 44 (n-type)/the sixth compoundsemiconductor layer (p-type). In addition, it is possible for thecurrent block layer 40 to have a three-layer structure arising from thestacking in the order of the sixth compound semiconductor layer(p-type)/the fourth compound semiconductor layer 44 (n-type)/the thirdcompound semiconductor layer 43 (p-type).

In the fourteenth, sixteenth, eighteenth, and twentieth embodiments, thesecond compound semiconductor layer has the two-layer structure composedof the second compound semiconductor layer 22A and the second compoundsemiconductor layer 22B stacked in that order from the active layerside. In the fifteenth, seventeenth, nineteenth, and twenty-firstembodiments, the second compound semiconductor layer has the two-layerstructure composed of the 2A-th compound semiconductor layer and the2B-th compound semiconductor layer stacked in that order from the activelayer side. In the former case, the second compound semiconductor layerof the two-layer structure is defined based on the change of the bandgap (or the refractive index). In the latter case, the second compoundsemiconductor layer of the two-layer structure is defined based on thechange of the impurity substitution site. Therefore, regarding themultilayer structure of the second compound semiconductor layerdescribed for the respective embodiments, if the second compoundsemiconductor layer has the two-layer structure composed of the 2A-thcompound semiconductor layer and the 2B-th compound semiconductor layerin particular, the 2A-th compound semiconductor layer can be regarded asthe second compound semiconductor layer 22A and the 2B-th compoundsemiconductor layer can be regarded as the second compound semiconductorlayer 22B. In addition, for example, it is also possible that the 2A-thcompound semiconductor layer is formed of the multilayer structurecomposed of the second compound semiconductor layers 22A and 22B, and itis also possible that the 2B-th compound semiconductor layer is formedof the multilayer structure composed of the second compoundsemiconductor layers 22A and 22B.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factor in so far as they arewithin the scope of the appended claims or the equivalents thereof.

1. A method for manufacturing a semiconductor light emitting device,comprising the steps of: (a) forming a plurality of mask layersextending along a <110> direction on a major surface of a substratehaving a {100} plane as the major surface, and exposing a part of themajor surface of the substrate between the mask layers; (b) epitaxiallygrowing an underlying layer composed of a III-V compound semiconductoron the exposed part of the major surface of the substrate, and thenremoving the mask layers, a sectional shape of the underlying layerobtained when the underlying layer is cut along a virtual planeperpendicular to the <110> direction of the substrate being a trapezoid,oblique surfaces of the underlying layer corresponding to two obliquesides of the trapezoid being {111}B planes, and a top surface of theunderlying layer corresponding to an upper side of the trapezoid being a{100} plane; (c) forming, above the top surface of the underlying layer,a light emitting part arising from sequential stacking of a firstcompound semiconductor layer of a first conductivity type, an activelayer, and a second compound semiconductor layer of a secondconductivity type, and forming, on an exposed major surface of thesubstrate on which the underlying layer is not formed, a multilayerstructure arising from sequential stacking of the first compoundsemiconductor layer of the first conductivity type, the active layer,and the second compound semiconductor layer of the second conductivitytype; and (d) forming, above the multilayer structure, a current blocklayer that covers at least an exposed side surface of the active layerof the light emitting part.
 2. The method for manufacturing asemiconductor light emitting device according to claim 1, wherein theunderlying layer composed of a material having an energy band gap largerthan an energy band gap of a material of the substrate is used.
 3. Themethod for manufacturing a semiconductor light emitting device accordingto claim 1, wherein the underlying layer composed of a material havingan energy band gap larger than an energy band gap of a material of thefirst compound semiconductor layer is used.
 4. The method formanufacturing a semiconductor light emitting device according to claim1, wherein the III-V compound semiconductor of the underlying layercontains, as an element, at least one of arsenic, antimony, and bismuth,and aluminum.
 5. The method for manufacturing a semiconductor lightemitting device according to claim 1, wherein the III-V compoundsemiconductor of the underlying layer contains at least phosphorus as anelement.
 6. A method for forming an underlying layer, comprising thesteps of: (a) forming a plurality of mask layers on a major surface of asubstrate, and exposing a part of the major surface of the substratebetween the mask layers; and (b) epitaxially growing an underlying layercomposed of a III-V compound semiconductor on the exposed part of themajor surface of the substrate, and then removing the mask layers,wherein an impurity whose substitution site is a site occupied by agroup III atom and an impurity whose substitution site is a siteoccupied by a group V atom are added to a material used for epitaxialgrowth of the underlying layer of an n conductivity type in order tocause the underlying layer to have the n conductivity type.
 7. Themethod for forming an underlying layer according to claim 6, wherein:the impurity whose substitution site is a site occupied by a group IIIatom is at least one kind of impurity selected from a group composed ofsilicon and tin; and the impurity whose substitution site is a siteoccupied by a group V atom is at least one kind of impurity selectedfrom a group composed of selenium, tellurium, and sulfur.
 8. The methodfor forming an underlying layer according to claim 6, wherein thesubstrate has the n conductivity type.
 9. The method for forming anunderlying layer according to claim 6, wherein: the substrate has a pconductivity type; subsequent to the step (a), a base layer of the pconductivity type is epitaxially grown on the exposed part of the majorsurface of the substrate, and then in the step (b), the underlying layercomposed of the III-V compound semiconductor is epitaxially grown on thebase layer instead of epitaxially growing the underlying layer composedof the III-V compound semiconductor on the exposed part of the majorsurface of the substrate; a tunnel junction is formed by the base layerand the underlying layer; and at least around an interface between thebase layer and the underlying layer and vicinity of the interface, animpurity whose substitution site is a site occupied by a group III atomand an impurity whose substitution site is a site occupied by a group Vatom are added to a material used for epitaxial growth of the base layerof the p conductivity type in order to cause the base layer to have thep conductivity type.
 19. The method for forming an underlying layeraccording to claim 9, wherein: the impurity whose substitution site is asite occupied by a group III atom in the base layer is at least one kindof impurity selected from a group composed of zinc, magnesium,beryllium, and manganese; and the impurity whose substitution site is asite occupied by a group V atom in the base layer is carbon.
 11. Amethod for forming an underlying layer, comprising the steps of: (a)forming a plurality of mask layers on a major surface of a substrate,and exposing a part of the major surface of the substrate between themask layers; and (b) epitaxially growing an underlying layer composed ofa III-V compound semiconductor on the exposed part of the major surfaceof the substrate, and then removing the mask layers, wherein an impuritywhose substitution site is a site occupied by a group III atom and animpurity whose substitution site is a site occupied by a group V atomare added to a material used for epitaxial growth of the underlyinglayer of a p conductivity type in order to cause the underlying layer tohave the p conductivity type.
 12. The method for forming an underlyinglayer according to claim 11, wherein: the impurity whose substitutionsite is a site occupied by a group III atom is at least one kind ofimpurity selected from a group composed of zinc, magnesium, beryllium,and manganese; and the impurity whose substitution site is a siteoccupied by a group V atom is carbon.
 13. The method for forming anunderlying layer according to claim 11, wherein the substrate has the pconductivity type.
 14. The method for forming an underlying layeraccording to claim 11, wherein; the substrate has an n conductivitytype; subsequent to the step (a), a base layer of the n conductivitytype is epitaxially grown on the exposed part of the major surface ofthe substrate, and then in the step (b), the underlying layer composedof the III-V compound semiconductor is epitaxially grown on the baselayer instead of epitaxially growing the underlying layer composed ofthe III-V compound semiconductor on the exposed part of the majorsurface of the substrate, a tunnel junction is formed by the base layerand the underlying layer; and at least around an interface between thebase layer and the underlying layer and vicinity of the interface, animpurity whose substitution site is a site occupied by a group III atomand an impurity whose substitution site is a site occupied by a group Vatom are added to a material used for epitaxial growth of the base layerof the n conductivity type in order to cause the base layer to have then conductivity type.
 15. The method for forming an underlying layeraccording to claim 14, wherein; the impurity whose substitution site isa site occupied by a group III atom in the base layer is at least onekind of impurity selected from a group composed of silicon and tin; andthe impurity whose substitution site is a site occupied by a group Vatom in the base layer is at least one kind of impurity selected from agroup composed of selenium, tellurium, and sulfur.